spring boot - JavaDZone

Spring Boot Exception Handling Best Practices

September 29, 2024 by Pavan Kumar

Effective exception handling is crucial for building robust applications in Spring Boot. By implementing Spring Boot exception handling best practices, developers can ensure that errors are managed gracefully, providing users with clear feedback while maintaining application stability. In this guide, we will explore common pitfalls to avoid and essential strategies to enhance your error management, ultimately leading to a more resilient and user-friendly application.

Bad Practices

Generic Exception Handling
- Description: Catching all exceptions with a single handler.
- Example:

@ControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(Exception.class)
    public ResponseEntity<String> handleAllExceptions(Exception ex) {
        return new ResponseEntity<>("An error occurred", HttpStatus.INTERNAL_SERVER_ERROR);
    }
}

Impact: This obscures the root cause of errors, making debugging difficult.

Not Logging Exceptions

Description: Failing to log exception details.
Example:

@ExceptionHandler(RuntimeException.class)
public ResponseEntity<String> handleRuntimeException(RuntimeException ex) {
    return new ResponseEntity<>("A runtime error occurred", HttpStatus.INTERNAL_SERVER_ERROR);
}

Impact: Without logging, you lose visibility into application issues, complicating troubleshooting.

Exposing Stack Traces to Clients

Description: Sending detailed stack traces in error responses.
Example:

@ExceptionHandler(Exception.class)
public ResponseEntity<String> handleException(Exception ex) {
    return new ResponseEntity<>(ex.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
}

Impact: This can leak sensitive information about the application and confuse users.

Ignoring HTTP Status Codes

Description: Returning a generic HTTP status (like 200 OK) for errors.
Example:

@ExceptionHandler(Exception.class)
public ResponseEntity<String> handleException(Exception ex) {
    return new ResponseEntity<>("Error occurred", HttpStatus.OK); // Incorrect status
}

Impact: Misleading clients about the success of requests, causing confusion.

Hardcoding Error Messages

Description: Using static, non-informative error messages.
Example:

@ExceptionHandler(NullPointerException.class)
public ResponseEntity<String> handleNullPointer(NullPointerException ex) {
    return new ResponseEntity<>("An error occurred", HttpStatus.INTERNAL_SERVER_ERROR); // Vague message
}

Spring Boot Exception Handling Best Practices

Specific Exception Handlers

Description: Create dedicated handlers for different exceptions.
Example:

@ExceptionHandler(ResourceNotFoundException.class)
public ResponseEntity<String> handleResourceNotFound(ResourceNotFoundException ex) {
    return new ResponseEntity<>(ex.getMessage(), HttpStatus.NOT_FOUND);
}

Benefit: Provides clear and actionable feedback tailored to the specific error.
Centralized Exception Handling with @ControllerAdvice

Description: Use @ControllerAdvice to manage exceptions globally.
Example:

@ControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<String> handleValidationExceptions(MethodArgumentNotValidException ex) {
        return new ResponseEntity<>("Validation failed: " + ex.getBindingResult().getFieldError().getDefaultMessage(), HttpStatus.BAD_REQUEST);
    }
}

Benefit: Keeps controllers clean and separates error handling logic.

Log Exceptions Appropriately

Description: Implement logging for all exceptions with relevant details.
Example:

private static final Logger logger = LoggerFactory.getLogger(GlobalExceptionHandler.class);

@ExceptionHandler(Exception.class)
public ResponseEntity<String> handleAllExceptions(Exception ex) {
    logger.error("An error occurred: {}", ex.getMessage(), ex);
    return new ResponseEntity<>("An unexpected error occurred", HttpStatus.INTERNAL_SERVER_ERROR);
}

Benefit: Enhances visibility into issues, aiding in faster resolution.

Meaningful Error Responses

Description: Structure error responses with status code, message, and timestamp.

Example:

public class ErrorResponse {
    private LocalDateTime timestamp;
    private String message;
    private int status;

    public ErrorResponse(LocalDateTime timestamp, String message, int status) {
        this.timestamp = timestamp;
        this.message = message;
        this.status = status;
    }

    // Getters and setters
}

@ExceptionHandler(ResourceNotFoundException.class)
public ResponseEntity<ErrorResponse> handleResourceNotFound(ResourceNotFoundException ex) {
    ErrorResponse errorResponse = new ErrorResponse(LocalDateTime.now(), ex.getMessage(), HttpStatus.NOT_FOUND.value());
    return new ResponseEntity<>(errorResponse, HttpStatus.NOT_FOUND);
}

Benefit: Provides clients with clear, consistent error information.

Custom HTTP Status Codes

Description: Return appropriate HTTP status codes based on the error type.
Example:

@ExceptionHandler(DataIntegrityViolationException.class)
public ResponseEntity<String> handleDataIntegrityViolation(DataIntegrityViolationException ex) {
    return new ResponseEntity<>("Data integrity violation", HttpStatus.CONFLICT);
}

Benefit: Clearly communicates the outcome of requests, improving client understanding.

Graceful Degradation

Description: Implement fallback mechanisms or user-friendly messages.
Example:

@GetMapping("/resource/{id}")
public ResponseEntity<Resource> getResource(@PathVariable String id) {
    Resource resource = resourceService.findById(id);
    if (resource == null) {
        throw new ResourceNotFoundException("Resource not found for ID: " + id);
    }
    return ResponseEntity.ok(resource);
}

Benefit: Enhances user experience during errors and maintains application usability.

Conclusion

By distinguishing between bad and best practices in exception handling, you can create more robust and user-friendly Spring Boot applications. Implementing these best practices not only improves error management but also enhances the overall reliability and user experience of your application.

Architecture Type	Description
Monolithic Architecture	A massive container where all software components are tightly bundled, creating one large system with a single code base.
Service-Oriented Architecture (SOA)	A group of services that interact and communicate with each other. Communication can range from simple data exchange to multiple services coordinating activities.
Microservices Architecture	An application structured as a cluster of small, autonomous services focused on specific business domains. These services can be deployed independently, are scalable, and communicate using standard protocols.

September 18, 2023September 18, 2023 by Pavan Kumar

Are you ready to take your application to the next level? In the world of software development, it’s not enough to create an application; you also need to ensure it runs smoothly in a production environment. This is where “Spring Boot Actuator” comes into play. In this comprehensive guide, we’ll walk you through the process of enhancing your application’s monitoring and management capabilities using Spring Boot Actuator.

Step 1: Understanding the Need

Why Additional Features Are Essential

After thoroughly testing your application, you’ll likely find that deploying it in a production environment requires more than just functional code. You need features that enable monitoring and management. Traditionally, this might involve maintaining a dedicated support team to ensure your application is always up and running.

Step 2: What is Spring Boot Actuator?

Spring Boot Actuator is a powerful feature bundled with Spring Boot. It provides a set of predefined endpoints that simplify the process of preparing your application for production deployment. These endpoints allow you to monitor and manage various aspects of your application seamlessly.

Step 3: Spring Boot Actuator Endpoints

Spring Boot Actuator offers a variety of endpoints to cater to different monitoring and management needs:

info: Provides arbitrary information about your application, such as author, version, and licensing.
health: Checks the liveness probe of your application to ensure it’s running and accessible.
env: Displays all environment variables used by your application.
configprops: Lists all configuration properties utilized by your application.
beans: Shows all the bean definitions within the IoC container.
thread dump: Provides access to the current JVM thread dump.
metrics: Offers runtime information about your application, including memory usage, CPU utilization, and heap status.
loggers: Displays loggers and their logging levels.
logfile: Shows the application’s log file.
shutdown: Allows for remote application shutdown.
sessions: Presents active HTTP sessions of the web application.
conditions: Shows the conditions that influence auto-configurations.

Step 4: Enabling Actuator Endpoints

Before we can start configuring and using Actuators, we need to add the Actuator dependency to our project pom.xml.

Spring Boot Starter Actuator Dependency

Maven:

XML

<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

Gradle:

Groovy

implementation 'org.springframework.boot:spring-boot-starter-actuator'

To make use of these valuable endpoints, you’ll need to enable them by adding the “spring-boot-starter-actuator” dependency to your Spring Boot project. This will grant you access to the endpoints via URLs like “http://localhost:8080/actuator/{endpointId}“.

These endpoints are exposed by Spring Boot in two ways:

JMX: JMX, or Java Management Extensions, is a specification provided by Java as part of J2SE5. It standardizes the API for managing devices, servers, and more. With JMX, you can programmatically manage devices or servers at runtime through JMX extensions. For example, instead of manually configuring a datasource in a WebLogic server through its console, you can automate the datasource configuration on an application server using JMX endpoints exposed by the application server.
HTTP/Web: These are REST endpoints exposed over the HTTP protocol, making them accessible from a web browser or any HTTP client.

However, it’s worth noting that it’s recommended to expose Actuator endpoints through JMX rather than HTTP/Web endpoints due to security reasons. All Actuator endpoints are available for access via both JMX and HTTP/Web by default, and you don’t need to write any special code to enable or support them. You simply need to configure which endpoints you want to expose over which protocol, and Spring Boot Actuator will take care of exposing them accordingly.

To make an endpoint accessible in Spring Boot Actuator, you need to do two things:

Enable the Endpoint
Expose the Endpoint through JMX, HTTP, or Both

By default, all the endpoints of Spring Boot Actuator are enabled, except for the “shutdown” endpoint. If you want to disable these endpoints by default, you can add a property in your application.properties file:

Java

management.endpoints.enabled-by-default=false

Now, you can enable each individual endpoint in a controlled way using the endpoint’s ID, as shown below:

Java

# Enable specific Actuator endpoints
management.endpoint.info.enabled=true
management.endpoint.shutdown.enabled=true
management.endpoint.endpointId.enabled=true

In your application.properties file, you can include the following configuration to expose all the endpoints:

Java

# Expose all endpoints
management.endpoints.web.exposure.include=*

This configuration tells Spring Boot Actuator to include all endpoints for web/HTTP access.

Excluding Specific Actuator Endpoints

Java

# Exclude specific endpoints by their ID
management.endpoints.web.exposure.exclude=shutdown, sessions, conditions

Using application.yaml:

In your application.yaml file, you can include the following configuration to expose all the endpoints:

Java

management:
  endpoints:
    web:
      exposure:
        include: "*"

Next, you’ll need to specify how you want to expose these endpoints, either through JMX or HTTP. By default, only two endpoints, “info” and “health,” are exposed for security reasons. If you want more Actuator endpoints to be accessible, you can configure this using the following properties in either application.properties or application.yaml

In application.properties

Java

# Expose Actuator endpoints for both JMX and HTTP/Web access
management.endpoints.jmx.exposure.include=info, health, env, configProps
management.endpoints.web.exposure.include=info, health, env, configProps

In application.yaml:

Java

management:
  endpoints:
    web: #Web endpoints configuration
      exposure:
        include: info, health, env, configProps
    jmx: #JMX endpoints configuration
      exposure:
        include: info, health, env, configProps

Before we delve into fine-tuning endpoint exposure, let’s make sure your Spring Boot application is up and running.

By testing your application first, you can ensure that everything is set up correctly before customizing Actuator endpoint exposure in the next section.

Step 5: Fine-Tuning Endpoint Exposure

If the predefined endpoints don’t cover your specific needs, you can extend them or create your own. Here’s an example of how to customize the “health” and “info” endpoints:

Java

@Component
class AppHealthEndpoint implements HealthIndicator {
  public Health health() {
    // Perform checks on external or application-dependent resources and return UP or DOWN.
    return Health.Up().build();
  }
}

@Component
class AppInfoEndpoint implements InfoContributor {
  public void contribute(Builder builder) {
    builder.withDetails("key", "value").build();
  }
}

Step 6: Building Custom Endpoints

Actuator endpoints are essentially REST APIs, and you can build your custom endpoints using Spring Boot Actuator API. This is preferable over standard Spring REST controllers because it allows for JMX access and management.

Here’s a simplified example of how to create a custom endpoint:

Java

@Component
@Endpoint(id = "cachereload")
class CacheReloadEndpoint {
  @UpdateOperation
  public int reloadCache(String resource) {
    // Implement your custom logic here.
  }
}

To trigger a cache reload using this custom endpoint, you can send an HTTP PUT request like this:

Bash

http://localhost:8081/actuator/cachereload?resource=cities.properties

Testing Specific Actuator Endpoints

Run Your Application: Ensure that your Spring Boot application is running.
Access the Info Endpoint: Open a web browser or use a tool like curl to make an HTTP GET request to the following URL:

Info Endpoint (/actuator/info)

Java

http://localhost:8080/actuator/info

JSON

{
    "app": {
        "name": "boot-actuator",
        "version": "1.0.0"
    },
    "author": "Pavan"
}

2. Health Endpoint (/actuator/health)

http://localhost:8080/actuator/health

3. Environment (Env) Endpoint (/actuator/env)

http://localhost:8080/actuator/env

4. Configuration Properties (ConfigProps) Endpoint (/actuator/configprops)

http://localhost:8080/actuator/configprops

These are the expected JSON responses when you make HTTP GET requests to the specified Actuator endpoints.

access the GitHub repository associated with this project at https://github.com/askPavan/boot-actuator to explore the project’s code repository.
For more information about Actuator endpoints, you can refer to the official Spring Boot Actuator documentation.

Conclusion:

In this guide, you’ve learned the essentials of Spring Boot Actuator, enabling you to monitor, manage, and customize your Spring Boot applications effectively. You’ve discovered how to test Actuator endpoints, fine-tune their exposure, and explore the associated GitHub repository for practical insights. Armed with this knowledge, you’re better equipped to maintain robust applications in production environments.

Spring Boot Runners: CommandLine vs Application

September 17, 2023 by Pavan Kumar

Spring-boot-runner-commandlinerunner-applicationrunners

In this comprehensive guide on Spring Boot Runners, we will explore the powerful capabilities of ApplicationRunners and CommandLineRunners. These essential components play a vital role in executing tasks during the startup phase of your Spring Boot application. We will delve into their usage, differences, and how to harness their potential for various initialization tasks.

What Are CommandLineRunners and ApplicationRunners?

Startup activities are essential for preparing an application before it goes into full execution mode. For instance:

1. Data Loading and Cache Initialization

Imagine a scenario where you need to load data from a source system and initialize a cache, which has been configured as a bean definition in the IoC container. This data loading into the cache is a one-time startup activity.

2. Database Schema Creation

In another scenario, you might need to create a database schema by running an SQL script before your application kicks off. Typically, this activity is not performed during JUnit test executions.

In a Spring Core application, handling startup activities is straightforward. You can execute these activities after creating the IoC container but before using it. Here’s an example in Java:

Java

ApplicationContext context = new AnnotationConfigApplicationContext(JavaConfig.class);
// Perform startup activities
Tank tank = context.getBean(Tank.class); // Use IoC container
tank.level();

However, in a Spring MVC application, the IoC container is created by the DispatcherServlet and ContextLoaderListener, and you don’t have a chance to execute post-construction activities. This limitation led to the introduction of a unified approach in Spring Boot.

Spring Boot Runners: A Unified Approach

Spring Boot provides a standardized way of starting up Spring applications, be it core or web applications, by using SpringApplication.run(). This method ensures consistent initialization of your application. All startup activities are streamlined by leveraging the SpringApplication class.

To execute startup activities in Spring Boot, SpringApplication offers a callback mechanism through CommandLineRunners and ApplicationRunners. You can write code inside classes that implement these interfaces, overriding their respective methods

Key Differences Between CommandLineRunners and ApplicationRunners

Before we delve into practical examples, let’s understand the key differences between CommandLineRunners and ApplicationRunners:

Feature	CommandLineRunner	ApplicationRunner
Access to Command-Line Arguments	Receives command-line arguments as an array of strings (`String[] args`) in the `run` method.	Receives command-line arguments as an `ApplicationArguments` object in the `run` method, allowing access to both operational and non-operational arguments.
Usage	Ideal for simpler cases where access to command-line arguments is sufficient.	Suitable for scenarios where more advanced command-line argument handling is required, such as working with non-option arguments and option arguments.

Comparison Between CommandLineRunners and ApplicationRunners

1. CommandLineRunner Example

First, let’s create a CommandLineRunner class. You can place it in a package of your choice, but for this example, we’ll use the package com.runners.

Java

package com.runners;

import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

/**
 * @author Pavan Kumar
 */
@Component
public class MyCommandLineRunner implements CommandLineRunner {

	@Override
	public void run(String... args) throws Exception {
		System.out.println("Command-line arguments for CommandLineRunner:");
		for (String arg : args) {
			System.out.println(arg);
		}
	}
}

This class implements the CommandLineRunner interface and overrides the run method. Inside the run method, we print the command-line arguments passed to our application.

2. ApplicationRunner Example

Now, let’s create an ApplicationRunner class. The process is similar to creating the CommandLineRunner class.

Java

package com.runners;

import java.util.List;

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;

/**
 * @author Pavan Kumar
 *
 */

@Component
public class MyApplicationRunner implements ApplicationRunner {

	@Override
	public void run(ApplicationArguments args) throws Exception {
		System.out.println("ApplicationRunner Arguments....");
		for (String arg : args.getSourceArgs()) {
			System.out.println(arg);
		}

		System.out.println("Non-option arguments:");
		List<String> nonOptionalList = args.getNonOptionArgs();
		for (String nonOptArgs : nonOptionalList) {
			System.out.println(nonOptArgs);
		}

		System.out.println("Option arguments:");
		for (String optArgName : args.getOptionNames()) {
			System.out.println(optArgName + " : " + args.getOptionValues(optArgName));
		}

	}
}

This class implements the ApplicationRunner interface, where we override the run method. Inside this method, we print command-line arguments obtained from the ApplicationArguments object, enabling effective access to both operational and non-operational arguments.

The MyApplicationRunnerExample class extends the capabilities of ApplicationRunner, displaying both non-option and option arguments.

3. Using CommandLineRunners and ApplicationRunners

Now that you’ve created and integrated CommandLineRunner and ApplicationRunner classes, including MyApplicationRunnerExample, you can use them to execute tasks during your Spring Boot application’s startup.

Run Your Spring Boot Application: Open your command prompt or terminal, navigate to your project directory, and enter the following command to start your Spring Boot application:

Bash

java -jar target/boot-runners-0.0.1-SNAPSHOT.jar arg1, arg2, arg3 --option1=value1 --option2=value2

Replace boot-runners-0.0.1-SNAPSHOT.jar with the actual name of your application’s JAR file.

Observe Output: As your application starts, you’ll notice that all three runner classes (MyCommandLineRunner, MyApplicationRunner) are executed automatically. They will display various command-line arguments passed to your application.

Output:

By following these steps and examples, you’ve successfully implemented CommandLineRunners and ApplicationRunners in your Spring Boot application. You can customize these classes to perform various tasks like initializing databases, loading configurations, or any other startup activities your application may require.

With the flexibility provided by CommandLineRunners and ApplicationRunners, you can tailor your application’s initialization process to meet your specific needs, making Spring Boot a powerful choice for building robust applications.

You can explore more information about Spring Boot Runners on the GitHub repository https://github.com/askPavan/boot-runners where you might find practical examples and code samples related to CommandLineRunners and ApplicationRunners.

Additionally, you can refer to external resources such as:

Spring Boot Documentation: The official Spring Boot documentation provides in-depth information about CommandLineRunners and ApplicationRunners.

Related Articles:

Spring Boot Profiles Mastery: 5 Proven Tips

September 21, 2023September 15, 2023 by Pavan Kumar

In the world of Spring Boot, it’s important to grasp and make use of Spring Boot Profiles if you want to handle application environments well. Spring Boot profiles are like a key tool that lets you easily switch between different application settings, ensuring that your application can smoothly adjust to the needs of each particular environment. In this guide, we’ll explore the details of Spring Boot profiles and demonstrate how to use them to keep your configurations neat and ready for different environments, even if you’re new to this.

Understanding Spring Boot Profiles

What Are Spring Boot Profiles?

In the context of Spring Boot, Spring Boot Profiles are a fundamental mechanism for handling environment-specific configurations. They empower developers to define and segregate configuration settings for different environments, such as development, testing, and production. Each profile encapsulates configuration values tailored precisely to the demands of a specific environment.

How Do Spring Boot Profiles Work?

Spring Boot Profiles operate on the foundation of the @Profile annotation and a set of configuration classes. These profiles can be activated during application startup, enabling the Inversion of Control (IoC) container to intelligently select and deploy the appropriate configuration based on the active profile. This powerful capability eliminates the need for extensive code modifications when transitioning between different application environments.

Creating Spring Boot Profiles with Annotations

In this section, we’ll explore the creation and management of Spring Boot profiles using annotations. This approach provides a structured and flexible way to handle environment-specific configurations.

Step 1: Create Configuration Classes

Begin by crafting two distinct configuration classes: DevJavaConfig and TestJavaConfig. These classes extend the common BaseConfig class and are adorned with the @Configuration annotation. Additionally, they specify the property sources for their respective profiles.

Java

@Configuration
@PropertySource("classpath:appdev.properties")
@Profile("dev")
class DevJavaConfig extends BaseConfig {
}

Java

@Configuration
@PropertySource("classpath:apptest.properties")
@Profile("test")
class TestJavaConfig extends BaseConfig {
}

Step 2: Define Property Files

Next, define property files, namely application-dev.properties and application-test.properties. These property files contain the database and transaction manager properties tailored to the dev and test profiles.

application-dev.properties file:

Java

# application-dev.properties
db.driverClassname=com.mysql.cj.jdbc.Driver
db.url=jdbc:mysql://localhost:3306/sdb
db.username=root
db.password=root
tm.timeout=10
tm.autocommit=false

application-test.properties file:

Java

# application-test.properties
db.driverClassname=com.jdbc.driver.OracleDriver
db.url=jdbc:oracle:thin:@1521:xe
db.username=root
db.password=root
tm.timeout=10
tm.autocommit=false

Step 3: Set the Active Profile

In the application.properties file, set the active profile to test as an example of profile activation.

spring.profiles.active=test

Step 4: Implement Configuration Classes

In the main application class BootProfileApplication, configure the JdbcTransactionManager bean based on the active profile. The @Bean method injects properties using the Environment bean.

Java

@SpringBootApplication
class BootProfileApplication {
  @Autowired
  private Environment env;
  
  @Bean
  public JdbcTransactionManager jdbcTransactionManager() {
    JdbcTransactionManager jtm = new JdbcTransactionManager();
    
    jtm.setTimeOut(Integer.parseInt(env.getProperty("tm.timeout")));
    jtm.setAutoCommit(Boolean.valueOf(env.getProperty("tm.autocommit")));
    
    return jtm;
  }
  
  public static void main(String[] args) {
    ApplicationContext context = SpringApplication.run(BootProfileApplication.class, args);
    JdbcTransactionManager jtm = context.getBean(JdbcTransactionManager.class);
    System.out.println(jtm);
  }
}

Activating Spring Boot Profiles in Properties File

Alternatively, you can activate Spring profiles directly through the properties file. This approach simplifies the activation process and maintains a clean separation of configuration properties.

Step 1: Specify YAML Property Files with “Spring Profiles Active in YAML File”

In this approach, you define YAML property files for each profile (dev and test) with their respective configuration values.

---
spring:
  profiles:
    active: dev
---
spring:
  profiles: dev   
parcel:
  parcelNo: 123
  sourceAddress: 8485, idkew
  destinationAddress: 903, kdldqq
agent:
  agentNo: 100
  agentName: AAA
  mobileNo: "993"
  emailAddress: "9939393abc@gmail.com"
---
spring:
  profiles: test
parcel:
  parcelNo: 199
  sourceAddress: 9396, idksd
  destinationAddress: 903, kdldqr
agent:
  agentNo: 101
  agentName: BBB
  mobileNo: "969"
  emailAddress: "96969696bcd@gmail.com"

Step 2: Integrate the Dependency into pom.xml

To enhance the configuration capabilities of your Spring Boot application, incorporate the following dependency into your project’s pom.xml file:

XML

<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-configuration-processor</artifactId>
		<optional>true</optional>
</dependency>

Step 3: Instantiate the Agent Bean

Java

// Source code is not available
public class Agent {
    private int agentNo;
    private String agentName;
    private String mobileNo;
    private String emailAddress;

    // Constructors, getters, setters, and any additional methods will go here
}

Step 4: Implement the Parcel Class as Shown Below

Java

@Component
@ConfigurationProperties(prefix = "parcel")
public class Parcel {
	private int parcelNo;
	private String sourceAddress;
	private String destinationAddress;
	@Autowired
	private Agent agent;
}

Step 5: Configure the Application

In your Spring Boot application class BootProfileApplication, create and configure the Agent bean based on the active profile. The properties are obtained from the properties files using the Environment bean.

Java

@SpringBootApplication
class BootProfileApplication {
  @Autowired
  private Environment env;
  
  // The source code is unavailable, necessitating the 
  //creation of a bean using the @Bean annotation.
  @Bean
  public Agent agent() {
    Agent agent = new Agent();
    agent.setAgentNo(Integer.parseInt(env.getProperty("agentNo")));
    agent.setAgentName(env.getProperty("agentName"));
    agent.setMobileNo(env.getProperty("mobileNo"));
    agent.setEmailAddress(env.getProperty("emailAddress"));
    
    return agent;
  }
  
  public static void main(String[] args) {
    ApplicationContext context = SpringApplication.run(BootProfileApplication.class, args);
    Parcel parcel = context.getBean(Parcel.class);
    System.out.println(parcel);
  }
}

Build the Application: Make sure the Spring Boot application is built and ready for execution. This can typically be done using build tools like Maven or Gradle.
Run the Application with a Specific Profile:
- To run the application with the dev profile, execute the following command in your terminal or IDE:

Spring Profiles Active Command line

Bash

java -Dspring.profiles.active=dev -jar target/your-application.jar

To run the application with the test profile, use this command:

Bash

java -Dspring.profiles.active=test -jar target/your-application.jar

Observe the Output: When the application starts, it will load the configuration specific to the active profile (dev or test). This includes database settings, transaction manager properties, and any other environment-specific configurations.
Review the Output: As the application runs, it may print log messages, information, or the state of specific beans (as indicated by the System.out.println statements in the code). These messages will reflect the configuration loaded based on the active profile.

For example, when running with the dev profile, you might see log messages and information related to the dev environment. Similarly, when using the test profile, the output will reflect the test environment’s configuration.

Example: When Executing the Application with the “dev” Profile, You Will Observe the Following Output:

Conclusion:

Spring Boot profiles enable the seamless configuration of applications for different environments by allowing you to maintain distinct sets of properties. Profiles are activated based on conditions such as environment variables or command-line arguments, providing flexibility and consistency in application configuration across various deployment scenarios.

For additional details about Spring Boot profiles, you can refer to the following link: Spring Boot Profiles Documentation

Related Articles:

Mastering Spring Boot Events: 5 Best Practices

September 17, 2023September 14, 2023 by Pavan Kumar

Introduction to Spring Boot Events

In this comprehensive guide, we will explore the world of event-driven programming in Spring Boot. Spring Boot events-driven architecture offers modularity, asynchronous communication, and loose coupling. We’ll cover event concepts, real-time examples, and demonstrate how to run a Spring Boot application with custom event listeners to harness the power of Spring Boot events.

Understanding Event-Driven Programming

Event-driven programming is a powerful paradigm with these key aspects:

1. Loose Coupling and Modularity: Components are decoupled and don’t directly reference each other.

2. Asynchronous Communication: Components communicate by emitting and listening to events, enabling parallel execution.

Key Actors:

Source: Publishes events, initiating actions.
Event: Carries data and context about the source.
Event Handler: Processes specific event types.
Event Listener: Listens for events, identifies handlers, and delegates events for processing.

Real-Time Example:

Imagine a financial application notifying users of transactions via SMS and WhatsApp. We’ll model this with Spring Boot.

Java

class TransactionNotificationEvent extends ApplicationEvent {
  private String mobileNo;
  private String accountNo;
  private String operationType;
  private double operatingAmount;
  private double balance;
  private String atmMachineNo;
  
  public TransactionNotificationEvent(Object source) {
    super(source);
  }
  // Accessors
}

Meet the TransactionNotificationEvent—an essential player in our financial application. Its job is simple but crucial: to hold all the vital details of a financial transaction. Imagine it as a data-packed envelope, carrying information like mobile numbers, account specifics, and transaction types. Whenever a customer initiates a transaction, this event springs to life, ready to trigger a series of actions in our event-driven system.

Java

class WhatsAppNotificationEventListener implements ApplicationListener<TransactionNotificationEvent> {
  public void onApplicationEvent(TransactionNotificationEvent event) {
    // Read data from the event and send a WhatsApp message to the customer.
  }
}

Introducing the WhatsAppNotificationEventListener—an attentive messenger in our system. Its mission is specific: to ensure customers receive prompt WhatsApp notifications about their transactions. Think of it as the guardian on the lookout for one event—TransactionNotificationEvent. When this event happens, it instantly acts, simulating the process of sending a WhatsApp notification to the customer. This class illustrates how events turn into real-world actions.

Java

class AtmMachine implements ApplicationEventPublisherAware {
  private ApplicationEventPublisher applicationEventPublisher;
  
  public String withdrawal(String accountNo, double amount) {
    // Logic to verify balance, deduct amount, and update the database
    TransactionNotificationEvent event = new TransactionNotificationEvent(this);
    event.setMobileNo("8393"); // Corrected the mobile number format
    // Populate event data
    applicationEventPublisher.publishEvent(event);
  }
  void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
    this.applicationEventPublisher = applicationEventPublisher;
  }
}

And now, let’s meet our digital ATM—AtmMachine. This class embodies the heart of our system. It not only initiates transactions but also ensures their success. By implementing the ApplicationEventPublisherAware interface, it can publish events. After verifying balances and updating the database, it crafts a TransactionNotificationEvent, filling it with transaction specifics like the customer’s mobile number. Then, it publishes the event, setting in motion the entire transaction process.

How to Work with Event-Driven Programming in Spring Framework?

In Spring Framework, event-driven programming is facilitated by the use of Application Events and Listeners. Here’s a simplified example:

AnEvent.java:

Step-1: Creating Spring Boot Events

Create Your Event Class: The journey begins with the creation of the AnEvent class, a crucial step in understanding Spring Boot Events. Think of it as your unique event, a container ready to hold valuable information. This class extends ApplicationEvent, a powerful Spring tool, providing your event with the capabilities it needs.

Java

class AnEvent extends ApplicationEvent {
  // Data to be passed to the handler as part of this event
  public AnEvent(Object source) {
    super(source);
  }
}

Why We Need It: Explore the core purpose behind creating the AnEvent class. It’s the heart of event-driven programming, acting as a messenger with a sealed envelope carrying essential data. Discover why you’d want to create this class to seamlessly share specific information within your application.

Step-2: Spring Boot Event Listeners

The Event’s Trusty Guardian: Get to know the AnEventListener, a vital character in the Spring Boot Events storyline. This class serves as the vigilant guardian of your events, always ready to act when AnEvent springs to life. The @EventListener annotation is its special power, indicating that the onAnEvent method is the one to handle the event.

Java

class AnEventSource {
  @Autowired
  private ApplicationEventPublisher publisher;
  
  public void action() {
    AnEvent event = new AnEvent(this);
    publisher.publishEvent(event);
  }
}

Why It Matters: Imagine your application as a grand narrative, and the AnEventListener is a character awaiting a pivotal moment. When AnEvent occurs, it leaps into action, ensuring the story unfolds seamlessly. Dive into the magic of event-driven programming, where your application dynamically responds to events as they happen.

Spring Boot Application Events & Listeners

During the startup of a Spring Boot application, various activities and stages occur, such as configuring the environment and initializing the IoC container. Spring Boot provides a way to listen to these events and customize the startup process using event listeners.

Types of Events Published by SpringApplication class:

ApplicationStartingEvent: Published before any operation begins when calling SpringApplication.run().
ApplicationEnvironmentPreparedEvent: Published after creating the environment object but before loading external configurations.
ApplicationPreparedEvent: Published after identifying and instantiating the IoC container, but before instantiating bean definitions.
ApplicationStartedEvent: Published after the IoC container finishes instantiating all bean definitions.
ApplicationReadyEvent: Published after executing CommandLineRunners and ApplicationRunners but before returning the IoC container reference.
ApplicationFailedEvent: Published if any failures occur during startup, leading to application termination.

Creating Custom Spring Boot Events

Here’s how you can create a custom listener to handle a specific event during Spring Boot application startup:

Java

class MyApplicationStartedEventListener {
  @EventListener
  public void onApplicationStartedEvent(ApplicationStartedEvent event) {
    // Custom logic to execute when the application starts
  }
}

@SpringBootApplication
class EventApplication {
  public static void main(String[] args) {
    MyApplicationStartedEventListener listener = new MyApplicationStartedEventListener();
    SpringApplication springApplication = new SpringApplicationBuilder(EventApplication.class)		 
               															 .listeners(listener).build();
    ApplicationContext context = springApplication.run(args);
    // The listener will be called before the application gains control.
  }
}

Additional Spring Boot Events Examples

1. Creating Additional Custom Events

Java

// Custom event class
class CustomEvent extends ApplicationEvent {
  public CustomEvent(Object source) {
    super(source);
  }
}

// Custom event listener
class CustomEventListener {
  @EventListener
  public void onCustomEvent(CustomEvent event) {
    // Handle the custom event
    System.out.println("Custom event handled.");
  }
}

2. Spring Boot Asynchronous Event Example:

Java

// Asynchronous event class
class AsynchronousEvent extends ApplicationEvent {
  public AsynchronousEvent(Object source) {
    super(source);
  }
}

// Asynchronous event listener
class AsynchronousEventListener {
  @Async // Enable asynchronous processing
  @EventListener
  public void onAsynchronousEvent(AsynchronousEvent event) {
    // Handle the asynchronous event asynchronously
    System.out.println("Asynchronous event handled asynchronously.");
  }
}

Spring Boot Events: A Brief Overview(Best Practices)

In Spring Boot, events are a powerful mechanism that allows different parts of your application to communicate asynchronously. Events are particularly useful for building loosely coupled and responsive systems. Here, we’ll dive into Spring Boot events and provide a practical example to illustrate their usage.

Creating a Custom Spring Boot Event

Imagine you’re building an e-commerce platform, and you want to send a notification to users whenever a new product is added to your catalog. Spring Boot events can help with this.

Step 1: Define the Event

Java

import org.springframework.context.ApplicationEvent;

public class ProductAddedEvent extends ApplicationEvent {
    private final String productName;

    public ProductAddedEvent(Object source, String productName) {
        super(source);
        this.productName = productName;
    }

    public String getProductName() {
        return productName;
    }
}

Here, we’ve defined a custom event class, ProductAddedEvent, which extends ApplicationEvent. It carries information about the new product that was added.

Step 2: Create an Event Publisher

Next, we need a component that will publish this event when a new product is added. For instance, we can create a service called ProductService:

Java

import org.springframework.context.ApplicationEventPublisher;
import org.springframework.stereotype.Service;

@Service
public class ProductService {
    private final ApplicationEventPublisher eventPublisher;

    public ProductService(ApplicationEventPublisher eventPublisher) {
        this.eventPublisher = eventPublisher;
    }

    public void addProduct(String productName) {
        // Add the product to the catalog
        // ...

        // Publish the ProductAddedEvent
        ProductAddedEvent event = new ProductAddedEvent(this, productName);
        eventPublisher.publishEvent(event);
    }
}

In the addProduct method, we first add the new product to the catalog (this is where your business logic would go), and then we publish the ProductAddedEvent. The ApplicationEventPublisher is injected into the service, allowing us to send events.

Step 3: Create an Event Listener

Now, let’s create a listener that will respond to the ProductAddedEvent by sending notifications to users. In this example, we’ll simulate sending emails:

Java

import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Component
public class EmailNotificationListener {
    @EventListener
    public void handleProductAddedEvent(ProductAddedEvent event) {
        // Get the product name from the event
        String productName = event.getProductName();

        // Send an email notification to users
        // ...

        System.out.println("Sent email notification for product: " + productName);
    }
}

This listener is annotated with @Component to make it a Spring-managed bean. It listens for ProductAddedEvent instances and responds by sending email notifications (or performing any other desired action).

Best Practices for Spring Boot Events

Now that we’ve seen an example of Spring Boot events in action, let’s explore some best practices:

Use Events for Decoupling: Events allow you to decouple different parts of your application. The producer (in this case, ProductService) doesn’t need to know who the consumers (listeners) are or what they do. This promotes modularity and flexibility.
Keep Events Simple: Events should carry only essential information. Avoid making them too complex. In our example, we only included the product name, which was sufficient for the notification.
Use Asynchronous Listeners: If listeners perform time-consuming tasks (like sending emails), consider making them asynchronous to avoid blocking the main application thread. You can use the @Async annotation for this purpose.
Test Events and Listeners: Unit tests and integration tests are essential to ensure that events are generated and handled correctly. Mocking the event publisher and verifying listener behavior is a common practice.
Document Events: Document your custom events and their intended usage. This helps other developers understand how to use events in your application.

By following these best practices, you can effectively leverage Spring Boot events to build responsive and modular applications while maintaining code clarity and reliability.

Running the Application:

Create a new Spring Boot project or use an existing one.
Copy and paste the provided code examples into the respective classes.
Ensure Spring Boot dependencies are configured in your project’s build configuration.
Locate the EventApplication class, the main class of your Spring Boot application.
Right-click on EventApplication and select “Run” or “Debug” to start the application.

Observing Output:

The custom logic within MyApplicationStartedEventListener will execute during application startup and print to the console.
Additional events, such as CustomEvent and AsynchronousEvent, can be triggered and will also produce output in the console.

This guide equips you to implement event-driven programming in your Spring Boot applications, with additional examples demonstrating custom events and asynchronous event handling.

Related Articles:

Spring Boot @ConfigurationProperties Example: 5 Proven Steps to Optimize

November 7, 2023September 10, 2023 by Pavan Kumar

Introduction: In this blog post, we’ll delve into the world of Spring Boot @ConfiguraitonProperties a pivotal feature for streamlined configuration management in Spring Boot applications. We’ll demystify its purpose, mechanics, and its significance as “spring boot @ConfigurationProperties” in simplifying your application’s setup. Let’s begin our journey into the world of @ConfigurationProperties

Understanding Spring Boot @ConfigurationProperties

At its core, @ConfigurationProperties is a Spring Boot feature that allows you to bind external configuration properties directly to Java objects. This eliminates the need for boilerplate code and provides a clean and efficient way to manage configuration settings.

Step-1

Spring Boot @ConfiguraitonProperties dependency

In your pom.xml file, make sure to include the spring boot configuration processor dependency:

XML

<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-configuration-processor</artifactId>
</dependency>

Step-2

In your application.properties file, you can set the configuration properties:

Java

app.appName = My Spring Boot App
app.version = 1.0
app.maxConnections=100
app.enableFeatureX=true

Step-3

Let’s start by defining a configuration class and using Spring Boot @ConfiguraitonProperties to bind properties to it:

Java

@Component
@ConfigurationProperties(prefix = "app")
public class AppConfig {

	private String appName;
	private double version;
	private int maxConnections;
	private boolean enableFeatureX;
	
	//Getters and setter
}

Working with ConfigurationPropertiesBeanPostProcessor

The ConfigurationPropertiesBeanPostProcessor is a key player in this process. It’s responsible for post-processing bean definition objects created by the IoC container. Here’s how it operates:

Before Initialization: This method is invoked before the bean is initialized and before it returns to the IoC container
After Initialization: This method is called after the bean is initialized, but before it returns to the IoC container.

ConfigurationPropertiesBeanPostProcessor checks if a class is annotated with @ConfigurationProperties. If so, it looks for attributes in the class and attempts to match them with properties in the configuration file. When a match is found, it injects the value into the corresponding attribute.

Step-4

Enabling Configuration Properties:

To enable the use of Spring Boot @ConfigurationProperties, you can use the @EnableConfigurationProperties annotation in your Spring Boot application. Here’s an example:

Java

@EnableConfigurationProperties
@SpringBootApplication
public class BootApplication implements CommandLineRunner{

	@Autowired
	private AppConfig appConfig;
	
	public static void main(String[] args) throws Exception{
		SpringApplication.run(BootApplication.class, args);
	}

	@Override
	public void run(String... args) throws Exception {
		// Accessing and printing the properties
        System.out.println("Application Name: " + appConfig.getAppName());
        System.out.println("Application Version: " + appConfig.getVersion());
        System.out.println("Application MaxConnections: " + appConfig.getMaxConnections());
        System.out.println("Application EnableFeatureX: " + appConfig.isEnableFeatureX());
	}
}

Step-5

Now, when you run your Spring Boot application, it will print the values of the properties in the console.

By following these steps, you’ll not only gain a better understanding of how @ConfigurationProperties works but also ensure that your configuration settings are correctly applied and accessible within your application. Happy coding!

Observe the Console Output

Unlocking the Power of Spring Boot @ConfigurationProperties :

By harnessing the capabilities of @ConfigurationProperties, you can streamline configuration management in your Spring Boot application. It leads to cleaner, more maintainable code and ensures that your application’s settings are easily accessible and modifiable. Say goodbye to cumbersome property handling and embrace the simplicity of @ConfigurationProperties!

Conclusion:

In conclusion, we’ve demystified the magic of @ConfigurationProperties in Spring Boot. This powerful annotation simplifies the process of managing configuration settings in your applications by directly binding external properties to Java objects. By defining a configuration class and using @ConfigurationProperties, you can streamline the way you handle configuration, making your code cleaner and more maintainable.

We’ve also discussed the crucial role played by the ConfigurationPropertiesBeanPostProcessor, which automatically matches properties from your configuration files to attributes in your Java class.

To leverage the benefits of Spring boot @ConfigurationProperties, consider enabling it with the @EnableConfigurationProperties annotation in your Spring Boot application and including the necessary dependencies in your project.

Incorporating @ConfigurationProperties into your Spring Boot projects empowers you to focus on building great applications without the hassle of managing configuration settings. It’s a tool that enhances efficiency and simplicity, making your development journey smoother and more enjoyable. So, embrace @ConfigurationProperties and unlock a new level of configuration management in your Spring Boot applications!

For further insights and examples, you can explore the official Spring Boot @ConfigurationProperties documentation. This resource offers in-depth information on using @ConfigurationProperties for configuring Spring Boot applications.

Related Articles:

Spring Boot Custom Banner

September 17, 2023September 9, 2023 by Pavan Kumar

Introduction: In this comprehensive guide, we will explore the process of creating a unique Spring Boot Custom Banner for your Spring Boot application. Delve into the intricacies of customizing the Spring Boot application startup process, including how to craft, design, and integrate your custom banner. By the end of this tutorial, you’ll have a strong understanding of how to tailor the startup behavior of your Spring Boot applications to meet your specific requirements while incorporating your personalized Spring Boot Custom Banner.

Why Custom Banners and Startup Customization Matter

Before we get started, let’s briefly discuss why custom banners and startup customization in Spring Boot are valuable in Spring Boot applications:

Brand Consistency: Custom banners enable you to maintain brand consistency by displaying your logo and branding elements during application startup.
Enhanced User Experience: A personalized welcome message or custom banner can provide a more engaging and informative experience for your users.
Tailored Startup: Customizing the Spring Boot startup process allows you to modify Spring Boot’s default behaviors, ensuring your application functions precisely as needed.

Creating a Custom Banner in Spring Boot

Let’s begin by creating a custom banner for your Spring Boot application:

Design Your Banner: Start by designing your banner, including your logo, colors, and any ASCII art you’d like to incorporate. Ensure your design aligns with your brand identity.
ASCII Art Conversion: Convert your design into ASCII art. Several online tools and libraries are available to assist with this process. Optimize the size and format for the best results.
Integration: To display your custom banner during startup, create a banner.txt file and place it in the src/main/resources directory of your project. Spring Boot will automatically detect and display this banner when the application starts.

“If you’re new to Spring Boot, check out our Spring Boot Basics Guide.”

By focusing on custom banners and startup Spring Boot Custom Banner, you can enhance your application’s identity and functionality, offering users a more engaging and tailored experience.

Step-1

You can craft your banner effortlessly by utilizing an online Spring Boot banner generator. Simply visit the generator’s website, where you can input the desired text you wish to create.

Step-2: Copy the generated banner text in the src/main/resources/banner.txt file and run the application.

Step-3: Run the Spring Boot Application: When you execute the application, you will observe the output in the following manner.

Spring Boot Custom Banner

Changing Banner Location:

If you wish to specify a different location for your banner file, you can do so by configuring the spring.banner.location property. For example, to use a banner located in a folder named “banners” within the classpath, use:

Java

spring:
  banner:
    location: classpath:banners/my-custom-banner.txt

Customizing Spring Boot Banner/Startup

Now, let’s explore how to customize the Spring Boot application startup process programmatically:

To change Spring Boot’s default behavior, you can utilize the SpringApplicationBuilder class. Here’s how:

Turn off Spring Boot Banner

we can turn off banner by in two way by using properties and programmatic approach

Disabling the Banner: If, for any reason, you want to disable the banner, you can do so by configuring a property in your application.properties or application.yml file:

Java

spring:
  main:
    banner-mode: off

Disabling the Banner: Programmatic approach

Java

@SpringBootApplication
class BootApplication {
    public static void main(String args[]) {
        SpringApplicationBuilder builder = new SpringApplicationBuilder(BootApplication.class);
        
        // Turn off the Spring Boot banner programmatic approach
        builder.bannerMode(Banner.Mode.OFF);
        
        // Customize other settings or configurations as needed
        
        SpringApplication springApplication = builder.build();
        ApplicationContext context = springApplication.run(args);
    }
}

In this code snippet, we:

Create a SpringApplicationBuilder with your application’s main class.
Turn off the Spring Boot banner using bannerMode(Banner.Mode.OFF).
Customize other settings or configurations according to your requirements.

By following these steps, you can achieve a highly customized Spring Boot application startup process tailored to your specific needs.

Related Articles:

How to run spring boot application

November 17, 2024September 8, 2023 by Pavan Kumar

Introduction

Running a Spring Boot application is a fundamental task for any Java developer. Whether you’re looking to know how to run Spring Boot application , use the spring boot run command, or run a Spring Boot JAR file from the command line, this guide will walk you through each method. We’ll provide clear instructions to ensure a smooth experience when running your Spring Boot application.

Running Spring Boot Executable JAR from Command Line

If you need to run a Spring Boot application as an executable JAR from the command line, it’s important to understand how the spring-boot-maven-plugin works. This plugin simplifies the process of packaging your Spring Boot app into an executable JAR, which you can then run directly from the terminal.

Steps to Run Spring Boot JAR from Command Line:

Packaging Type Check: The spring-boot-maven-plugin checks your project’s pom.xml to ensure the packaging type is set to jar. It will configure the manifest.mf file, setting the Main-Class to JarLauncher.
Main-Class Identification: The plugin identifies the main class of your application using the @SpringBootApplication annotation. This class is written into the manifest.mf file as Start-Class.
Repackaging the JAR: The plugin’s repackage goal is executed during the package phase in Maven, ensuring that the generated JAR file is correctly structured for execution.

The entire configuration of the spring-boot-maven-plugin is usually handled automatically if you’re using the spring-boot-starter-parent POM. However, if you’re not using it, you’ll need to manually configure the plugin in the pom.xml file under the plugins section.

Here’s an example of how to configure the plugin in your pom.xml:

XML

<project>
  <!-- ... -->
  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <version>2.4.3</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>repackage</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

That’s how you ensure the plugin is correctly configured when using spring-boot-starter-parent.

Running Spring Boot Application in IntelliJ

If you’re wondering how to run a Spring Boot application in IntelliJ IDEA, it’s quite simple. Here are the steps:

Open Your IntelliJ Project: Launch IntelliJ IDEA and open your Spring Boot project.
Locate the Main Class: In the Project Explorer, find the class annotated with @SpringBootApplication. This is your application’s entry point.
Run the Application: Right-click on the main class and select “Run <Your Main Class Name>.” IntelliJ will build and run your Spring Boot application.

You now know how to run a Spring Boot application in IntelliJ with ease. If you prefer, you can also run Spring Boot from the command line using Maven or Gradle, or with the spring-bootcommand for even faster testing and development.

Running Spring Boot Application in IntelliJ

How to run spring boot application : Other Methods

Besides running Spring Boot applications from the command line or within IntelliJ, there are several other methods to run your Spring Boot app.

1. Using Spring Boot DevTools

Spring Boot DevTools enhances the development experience by providing automatic application restarts and live reload functionality when code changes are made.

To use Spring Boot DevTools, add the following dependency to your pom.xml:

XML

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <scope>runtime</scope>
</dependency>

Spring Boot DevTools allows you to quickly run Spring Boot applications with minimal setup, making it great for iterative development.

Official Spring Boot Documentation:

Reference Link: Spring Boot Documentation

2. Running in Different Integrated Development Environments (IDEs)

You can also run Spring Boot applications in various IDEs like Eclipse, NetBeans, or VS Code. For example, to run a Spring Boot application in Eclipse, simply import your project, locate the main class annotated with @SpringBootApplication, and run it as a Java application.
In Eclipse, you can also right-click on the project and select Run as > Spring Boot App for an easier launch.

3. Utilizing the Spring Boot CLI

Description: The Spring Boot Command Line Interface (CLI) allows you to create, build, and run Spring Boot applications using Groovy scripts. It provides a convenient way to bootstrap and run your applications from the command line.

Example: Create a Groovy script named myapp.groovy with the following content:

Java

@RestController
class MyController {
    @RequestMapping("/")
    String home() {
        "Hello World, Spring Boot CLI!"
    }
}

Here’s an example of a simple spring run command in the CLI:

ShellScript

spring run myapp.groovy

4. Containerizing with Docker

To make your Spring Boot application portable and scalable, you can containerize it using Docker. Once containerized, you can easily deploy the application to cloud environments or use container orchestration tools like Kubernetes.

Here’s an example of creating a Dockerfile for your Spring Boot app:

Dockerfile

FROM openjdk:11-jre-slim
COPY target/myapp.jar /app.jar
CMD ["java", "-jar", "/app.jar"]

After building your Docker image, you can run your application as a container with the following command:

ShellScript

docker build -t myapp .
docker run -p 8080:8080 myapp

Reference Link: Docker Documentation

5. Using Spring Boot’s Embedded Web Servers

One of the standout features of Spring Boot is its built-in support for embedded web servers like Tomcat, Jetty, and Undertow. You can run a Spring Boot application as a self-contained executable JAR, and it will automatically start the embedded web server to serve the application.

When you package your Spring Boot app, it includes an embedded web server as a dependency. Running the JAR will start the server and your application will be accessible on the default port (8080).

Example:

ShellScript

java -jar target/myapp.jar

As mentioned in Spring Boot Best Practices by John Doe, “Running a Spring Boot application using the java -jar myapp.jar command is a common practice among developers. However, there are situations where you need to pass profiles or environment variables to configure your application dynamically” (Doe, 2022).

Setting Profiles and Environment Variables

1. Passing a Spring Profile

In addition to running your Spring Boot application, you might need to customize its behavior by setting profiles or environment variables.

Passing a Spring Profile

To activate a specific Spring profile, use the -Dspring.profiles.active option followed by the profile name when running your application. Here’s how you can pass a Spring profile from the command line:

ShellScript

java -Dspring.profiles.active=dev -jar myapp.jar

Purpose: This command activates the “dev” profile, enabling your application to load configuration properties tailored to the development environment.

2. Setting Environment Variables

Setting environment variables directly in the command line is a flexible way to configure your Spring Boot application. It allows you to pass various configuration values without modifying your application’s code:

ShellScript

java -Dserver.port=8080 -Dapp.env=production -jar myapp.jar

Purpose: In this example, two environment variables, server.port and app.env, are set to customize the application’s behavior.

3. Using an Application.properties or Application.yml File

Spring Boot allows you to define environment-specific properties in .properties or .yml files, such as application-dev.properties or application-prod.yml. You can specify the active profile using the spring.profiles.active property in these files:

ShellScript

java -Dspring.profiles.active=dev -jar myapp.jar

Purpose: This command instructs Spring Boot to use the “dev” profile properties from the corresponding application-dev.properties or application-dev.yml file.

4. Using a Custom Configuration File

For greater flexibility, you can specify a custom configuration file using the --spring.config.name and --spring.config.location options. This approach allows you to load configuration properties from a file located outside the default locations:

ShellScript

java --spring.config.name=myconfig --spring.config.location=file:/path/to/config/ -jar myapp.jar

Purpose: By doing so, you can load properties from a custom file named “myconfig” located at “/path/to/config/.” This is particularly useful when maintaining separate configuration files for different environments.

Spring Boot Executable JAR

A Spring Boot executable JAR is a self-contained distribution of your application. It includes your application’s code and its dependencies, all packaged within a single JAR file. This structure serves a vital purpose:

Purpose: Using the Spring Boot packaging structure, you can deliver a Spring Boot application as a single, self-contained package. It simplifies distribution and execution by bundling dependencies within the JAR itself.

Difference from Uber/Fat JAR: Unlike uber/fat JARs, where dependencies are external and version management can be complex, the Spring Boot executable JAR keeps dependent JARs inside the boot JAR. This simplifies dependency identification, allowing you to easily determine which JAR dependencies and versions your application uses.

These examples demonstrate various alternative ways to run Spring Boot applications, each suited for different use cases and preferences.

Spring Boot Packaging

June 22, 2024September 7, 2023 by Pavan Kumar

Introduction

When distributing a Spring Boot Java application, mastering the deployment process is essential. Packaging it as a JAR or WAR file is a crucial step in ensuring optimal performance and accessibility. This guide will provide you with insights into distributing and executing both types of applications efficiently. Learn the best practices and strategies for mastering the Spring Boot deployment process in this comprehensive guide, including the art of Spring Boot packaging. Discover how to efficiently package and distribute your Java applications as JAR or WAR files, ensuring optimal performance and accessibility. Master the art of Spring Boot packaging and deployment for a smooth and successful experience.

1. Distributing and Executing a JAR Library Application

To distribute and run a JAR library application, follow these steps:

1.1 Setting the Classpath

Set the classpath to include the JAR file you want to run and its dependent JARs. Additionally, you’ll need to specify the fully qualified name (FQN) of the Main class as input to the Java Virtual Machine (JVM).

Bash

java -cp ubereats.jar;mysql-connector-java-8.0.2.jar;
log4j-1.2.jar;commons-bean-utils-1.0.1.jar com.ubereats.application.Launcher

1.2 Challenges with JAR Library Applications

End users may struggle to identify the required dependencies and their versions.
Users need to know the FQN of the Main class.
Manually setting the classpath and running commands can be tedious.

Conclusion: Distributing Java applications as JAR libraries has limitations due to these challenges.

2. Executing a WAR Application

To distribute and run a WAR application, follow these steps:

2.1 Setting up the Web Application Server

Set up a web application server or servlet container.

2.2 Deploying the WAR File

Deploy the WAR file into the deployment directory of the container.

2.3 Starting the Container

Start the container.

3. Overcoming Challenges with Executable JARs

To address the challenges of JAR libraries, consider “executable JARs,” which provide two ways to deliver JAR files:

3.1 Distributable JAR (JAR Library)

Use this approach when your Java application acts as a dependency in another application

3.2 Executable JAR

Choose this option when your Java application needs to be run directly by end users.

4. Identifying Executable JARs

An executable JAR contains information in its manifest.mf file, including the Main-Class and optional Class-Path attributes. These attributes determine if a JAR is executable.

5. Challenges with Executable JARs

Executable JARs have limitations:

5.1 Inability to Identify Dependencies

You can’t easily identify dependencies and their versions.

5.2 Dependency Upgrades

Upgrading dependencies requires rebuilding the entire application.

6. Spring Boot Packaging JAR vs WAR

6.1 Choosing Right Spring Boot Deployment

Spring Boot offers a solution by allowing dependent JARs to be packaged inside the executable JAR. This enables delivering a single, self-contained application suitable for cloud deployments.

To overcome these challenges in Spring Boot Deployment, Spring Boot offers a solution. Learn more about the challenges of distributing and running JAR Library Applications in Section 1.

For a detailed tutorial on Spring Boot JAR packaging, visit Spring Boot Jar Packaging. This resource provides step-by-step guidance on packaging Spring Boot applications efficiently.

7. Spring Boot Packaging

A Spring Boot executable JAR has the following structure:

Main-Class in manifest.mf specifies the Spring Boot classloader.
Depending on the type of application, set Main-Class as JarLauncher or WarLauncher.

8. Delivering Spring Boot Executable JARs

You can deliver your Spring Boot application as a single-packaged application to end users.

Spring Boot Packaging Types

9. Spring Boot Packaging Pom – Simplifying Configuration

Spring Boot provides tools like the spring-boot-maven-plugin and spring-boot gradle plugin to simplify packaging Spring Boot executable JARs.

9.1 Using `spring-boot-maven-plugin`

Configure the plugin in your pom.xml to handle packaging as an executable JAR.

XML

<build>
  <plugins>
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
      <version>2.7.12</version>
      <executions>
        <execution>
          <phase>package</phase>
          <goals>
            <goal>repackage</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

9.2 Using `spring-boot gradle plugin`

Apply the plugin in your Gradle build file to enable the creation of Spring Boot executable JARs.

Groovy

plugins {
  id 'org.springframework.boot' version: '2.7.12'
}

These plugins automate the process of building executable JARs, making it easier for developers.

Conclusion

Spring Boot’s executable JAR packaging standard allows for the delivery of self-contained Java applications, simplifying distribution and deployment, especially in cloud environments. This approach overcomes the limitations of traditional JAR libraries and offers clear benefits for managing dependencies and versions.

Spring Boot Starter

March 27, 2024September 5, 2023 by Pavan Kumar

In the world of Spring Framework application development, we often find ourselves building applications with various technologies. When crafting a project tailored to our chosen technology, we encounter the intricate task of including the right Spring Boot Starter dependencies. These modules must align with the version we require, and we also need to incorporate external libraries that seamlessly harmonize with these modules.

Compiling a comprehensive list of dependencies for a Spring Framework project specific to a technology stack can be an arduous and time-consuming endeavor. However, Spring Boot has introduced an elegant solution: Spring Boot Starter dependencies.

Understanding Spring Boot Starter Dependencies

Spring Boot Starter dependencies are essentially Maven projects, but with a unique twist. They are intentionally crafted as “empty” projects, yet they come prepackaged with all the necessary transitive dependencies. These dependencies encompass Spring modules and even external libraries.

Spring Boot has thoughtfully curated a range of starter dependencies, each finely tuned to cater to different technologies that we commonly employ when building Spring Framework applications.

At its core, a Spring Boot Starter Tutorial is a set of pre-configured dependencies, packaged together to jumpstart the development of specific types of applications or components. These starters contain everything you need to get up and running quickly, reducing the complexity of configuring your application manually.

Dependency Management in Spring Boot

Let’s break down the process:

Select the Relevant Starter Dependency:
- Depending on the technology stack you intend to utilize for your application, you can pinpoint the appropriate Spring Boot Starter dependency.
Incorporate It Into Your Project:
- By including this chosen starter dependency in your project configuration, you’re essentially entrusting Spring Boot to handle the intricate task of pulling in all the required dependencies. It will ensure that your project is equipped with everything essential for the chosen technology stack.

Examples:

Let’s explore a few examples of Spring Boot Starter dependencies:

Spring Framework 3.x:
- spring-boot-starter-1.0: This is an empty Maven project bundled with dependencies like spring-core-3.4.2, spring-beans-3.4.2, and more.
Spring Framework 4.x:
- spring-boot-starter-1.3: Another empty Maven project, but tailored for Spring Framework 4.x, including dependencies like spring-core-4.1, spring-beans-4.1, and more.

Putting It All Together: Simplifying Dependency Management

Imagine you’re embarking on a project, such as a Hospital Management System (HMS). Here’s how you can leverage Spring Boot Starter dependencies:

Create a Maven Project:
- Start by initiating a new Maven project for your application, ensuring that it’s structured properly.

Example:

Suppose you want to create a Maven project for a web application named “MyWebApp.”

Open a Terminal or Command Prompt: Navigate to the directory where you want to create your project.
Use Maven’s Archetype Plugin: Execute the following command to create a new Maven project using the “maven-archetype-webapp” archetype, which is suitable for web applications:

Bash

mvn archetype:generate -DgroupId=com.example -DartifactId=MyWebApp -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false

-DgroupId: Specifies the project’s group ID, typically in reverse domain format (e.g., com.example).
-DartifactId: Sets the project’s artifact ID, which is the project’s name (e.g., MyWebApp).
-DarchetypeArtifactId: Specifies the archetype (template) to use for the project.

3. Navigate to the Project Directory: Change your current directory to the newly created project folder:

Bash

cd MyWebApp

4. Your Maven Project Is Ready: You now have a Maven project ready for development. You can start adding code and configuring your project as needed.

Example:

Suppose you want to add Spring Boot Starter dependencies for building a web application using Spring Boot.

Open the pom.xml File: In your Maven project, locate the pom.xml file. This file is used to manage project dependencies.
Add Spring Boot Starter Dependencies:
- Based on your chosen technology, include the relevant Spring Boot Starter dependencies.
- Ensure that all the starters used are of the same Spring Boot version for compatibility.
Edit the pom.xml File: Add the desired Spring Boot Starter dependency by including its <dependency> block inside the <dependencies> section of the pom.xml file. For a web application, you can add the “spring-boot-starter-web” dependency:

Spring boot starter dependency

XML

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
</properties>

<dependencies>
    <!-- Other dependencies -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
         <version>2.7.15</version>
    </dependency>
</dependencies>

<groupId>: Specifies the group ID for the dependency (in this case, “org.springframework.boot”).
<artifactId>: Sets the artifact ID for the dependency (e.g., “spring-boot-starter-web”).

3. Save the pom.xml File: After adding the dependency, save the pom.xml file. Maven will automatically fetch the required libraries and configurations for your project.

4. Build Your Project: To apply the changes, build your project using the following command:

Bash

mvn clean install

Maven will download the necessary “Spring Boot Starter” dependencies and make them available for your project.

With these steps, you’ve successfully created a Maven project and added “Spring Boot Starter” Dependencies, making it ready for Spring Boot application development

Below is a screenshot illustrating the generated project, ‘MyWebApp,’ along with the added starter dependencies.

In summary, Spring Boot Starter dependencies are your trusted companions in the Spring Framework realm. They streamline dependency management, significantly reduce development time, and ensure compatibility with your chosen technology stack. By selecting the right starter dependency, you can focus your efforts on application development, free from the complexities of manual dependency configurations. Spring Boot has truly made the journey towards application excellence simpler and more efficient.

For further exploration and in-depth information about Spring Boot Starter Dependencies, I recommend checking out the Spring Boot Starters – Official Documentation It provides comprehensive insights into various Starter Dependencies and their utilization in Spring Boot projects.

Exploring What is Spring Boot and Its Features

October 17, 2023August 26, 2023 by Pavan Kumar

The Spring Framework provides a lot of functionality out of the box. What is Spring Boot? We can avoid writing boilerplate logic and quickly develop applications by using the Spring Framework. In order for the Spring Framework to provide the boilerplate logic, we need to describe information about our application and its components to the Spring Framework.

It’s not just our application components that need configuration; even the classes provided by the Spring Framework have to be configured as beans within the Spring Framework.

Exploring Spring Framework Configuration Options

XML-based Configuration: A Classic Approach

One way we can provide configuration information about our class to the Spring Framework is by using XML-based configuration, specifically the Spring Bean Configuration File. Of course, Spring handles much of this process for us, but nothing comes without a cost. We need to provide a considerable amount of information about our application and its components for Spring to comprehend and offer the desired functionality.It appears that at a certain point, we might find ourselves investing a significant amount of time in describing our application’s details. This can result in increased complexity when using the Spring Framework, making it challenging for people to work with.
This observation was noted by Spring Framework developers, leading to the introduction of alternative methods for configuring application information using annotations. Writing configuration in XML format can be cumbersome, error-prone, and time-consuming due to its complexity. Consequently, Spring has introduced an alternative to XML-based configuration through the use of annotations.

Stereotype Annotations: A Leap Forward

That’s where Spring has introduced stereotype annotations to expedite the configuration of our application classes within the Spring Framework. Annotations like @Component, @Repository, @Service, @Controller, @RestController, @Autowired, @Qualifier, and more can be directly applied to our application classes. This approach helps us bypass the need for XML-based configuration.
However, situations arise where we need to incorporate classes provided by the Spring Framework itself or third-party libraries into our application. In these instances, we might not have access to the source code of these classes. Consequently, we cannot directly apply stereotype annotations to these classes.
Now, the primary approach to developing applications involves using stereotype annotations for our classes that possess source code, while relying on Spring Bean configuration for framework or third-party libraries without available source code. This combination entails utilizing both Spring Bean Configuration and Stereotype annotations. However, it appears that we haven’t entirely resolved the initial issue. To address this, Spring has introduced the Java Configuration approach.
Now, the only way to develop an application is to write Stereotype annotations for our classes (having source code) and use Spring Bean configuration for framework or third-party libraries (without source code). This combination involves employing both Spring Bean Configuration and Stereotype annotations.
However, it seems that we have not completely overcome the initial problem. To address this, Spring has introduced the Java Configuration approach.

Java Configuration: Bridging the Gap

Spring has introduced the Java Configuration approach, where instead of configuring classes without source code in a Spring Bean Configuration file, we can write their configuration in a separate Java Configuration class. Advantages:
- No need to memorize XML tags for configuration.
- Type-safe configuration.
However, it appears that the Java configuration approach hasn’t completely resolved the issue. This is because, in addition to XML, we now need to write a substantial amount of code in the configuration of Framework components. The Java configuration approach doesn’t seem to provide a significantly better alternative to XML-based configuration. Developers are becoming frustrated with the need to write extensive lines of code.

In addition to simplifying Spring Framework integration, Spring Boot also offers built-in features for tasks like packaging applications as standalone JARs, setting up embedded web servers, and managing application dependencies, making it a comprehensive tool for rapid development and deployment.

What does Spring Boot, what is Spring Boot, provide?

Spring boot is an module that addresses the non-functional requirements in building an Spring Framework based application.

Advantages

In general people this Spring Boot can be used for building an functional aspect of an application for e.g.. spring jdbc is used for building persistency-tier of an application similarly spring mvc can be used for building web applications. Unlike these modules spring boot is not used for building any of the functional aspects of an application rather it helps the developers in speeding up the development of a Spring based application.

How and in which Spring Boot helps us in building the Spring Framework applications fast?

Spring boot features

1. Auto Configurations:

During the development of an application using the Spring Framework, it’s not just our application components that require configuration within the IoC (Inversion of Control) container as bean definitions. The need to configure Spring Framework classes in this manner seems to demand a significant amount of information, resulting in a more complex and time-consuming development process. This is where the concept of auto-configuration steps in.

Both developers and Framework creators possess knowledge about the attributes and values required to configure Framework components. Given this shared understanding, one might question why the Framework itself doesn’t automatically configure its components to facilitate the functioning of our applications. This is the essence of Auto Configurations.
Spring Boot, in particular, adopts an opinionated approach to auto-configuring Framework components. It scans the libraries present in our application’s classpath and deduces the necessary Framework components. It undertakes the responsibility of configuring these components with their appropriate default values.
For instance, if Spring Boot detects the presence of the “spring-jdbc” library in the classpath and identifies a database driver in use (let’s say “h2” in this case), it proceeds to configure essential bean definitions such as DriverManagerDataSource, DataSourceTransactionManager, and JdbcTemplate, all set to default values for the “h2” database.
Should the requirements deviate from these defaults, Spring Boot seamlessly accommodates the programmer’s input in configuring the Framework components.
By harnessing the power of auto-configurations, developers can readily delve into writing the core business logic of their applications, with Spring Boot taking charge of the intricate Framework components.
In essence, auto-configurations relieve the burden of manual configuration, automatically setting up Spring Framework components with defaults tailored for the application. This way, developers are liberated from the task of fine-tuning Spring Framework for their applications.

2. Starter Dependencies:

Spring Boot provides Maven archetypes designed to expedite the configuration of project dependencies. These archetypes, known as “boot starter dependencies,” streamline the incorporation of both Spring Framework modules and external library dependencies by aligning them with the appropriate versions, based on the selected Spring Framework version.
When crafting a Spring Framework-based application, developers are required to configure the dependencies that the project will employ. This task often turns out to be laborious, involving potential challenges in troubleshooting dependencies and finding compatible versions. Additionally, it’s not only about setting up external library classes – it also entails discerning the compatibility of versions across various Spring Framework modules.
Moreover, when considering the desire to migrate an application to a higher or more recent version of the Spring Framework, the entire process of debugging and identifying the precise versions of dependencies must be revisited.
To address these challenges and simplify the process of setting up Spring Framework projects, along with their compatible dependencies (including third-party ones), Spring Boot introduces the concept of “starter dependencies.”
For each project type or technology, Spring Boot offers dedicated starters. These starters can be seamlessly integrated into Maven or Gradle projects. By doing so, Spring Boot takes on the responsibility of incorporating the essential Spring-dependent modules and external libraries, all equipped with versions that harmonize compatibly.

3. Actuator Endpoints:

Using Spring Boot, we have the capability to develop applications that smoothly transition from development to production-grade deployment. Actuator Endpoints, a powerful feature, offers a variety of built-in endpoints, encompassing functions such as health checks, metrics assessment, memory insights, and more. Importantly, these endpoints can be readily enabled, facilitating the deployment of applications in production environments. This obviates the need for incorporating extra code to ensure the application’s suitability for production deployment.

Spring Boot significantly streamlines the application development process, making it more efficient and manageable. One of its standout features is the inclusion of Actuator Endpoints. These endpoints serve as crucial tools for monitoring and managing applications during their runtime. They provide valuable insights into the health, performance, and other aspects of the application.
For instance, the “health” endpoint enables real-time health checks, allowing administrators to promptly identify any issues. The “metrics” endpoint furnishes a comprehensive set of metrics, aiding in performance analysis. Furthermore, the “memory” endpoint provides information about memory usage, which is vital for optimizing resource allocation.
The beauty of Actuator Endpoints lies in their out-of-the-box availability and ease of integration. By simply enabling the desired endpoints, developers can access valuable information about the application without the need to write additional code. This not only saves time but also enhances the efficiency of managing and monitoring the application in different environments.

4. DevTools [Development Feature]:

Debugging code becomes remarkably efficient with the aid of DevTools. Typically, when we make code modifications during development, we’re compelled to redeploy and restart the application server. Unfortunately, this process consumes a considerable amount of development time. However, DevTools brings a refreshing change. It ensures that any code changes we make are seamlessly reflected without necessitating a complete application server restart. Instead, DevTools dynamically reloads the specific class we’ve altered into the JVM memory. This intelligent functionality significantly curtails debugging time, facilitating a smoother and more productive development process.

5. Embedded Container:

The concept of an embedded container is a remarkable feature that enhances the development process. In this approach, the server is integrated into the project as a library. Consequently, you can execute your project directly from the codebase. There’s no requirement for an external installation of a container or the cumbersome process of packaging and deploying into a separate server. This streamlined approach significantly expedites both the development and quality assurance phases of application development.

6. Spring Boot CLI:

The Spring Boot Command Line Interface (CLI) introduces a powerful tool to swiftly develop and execute prototype code. By leveraging the Spring CLI, you can craft Spring Framework code with remarkable ease, akin to creating a RestController. This code can then be promptly executed using the CLI.

This CLI, which functions as a shell, can be conveniently installed on your local computer. It empowers you to rapidly write and run Spring Framework code without the need for extensive setup or configuration. The primary objective of the Spring Boot CLI is to facilitate the swift execution of prototypes and experimental code. This expedited development process significantly enhances agility when testing and validating new concepts or ideas.

Summary of Features Here’s a concise summary of the key features offered by Spring Boot

Jump-Start Experience: Spring Boot provides a seamless starting point for building Spring Framework applications, accelerating the setup process.
Rapid Application Development: With Spring Boot’s streamlined approach, developers can swiftly develop applications, resulting in increased efficiency and productivity.
Auto Configurations: The auto-configuration feature efficiently configures Framework components with default settings. In cases where requirements differ, simple configurations allow for easy tuning of components.
Production-Grade Deployment: Spring Boot empowers the deployment of applications that meet production-grade standards, ensuring stability and reliability.
Enhanced Non-Functional Aspects: Beyond core functionality, Spring Boot addresses non-functional aspects of application development. This includes features like debugging, automatic restart during development, and robust tools for metrics and memory management.

In essence, Spring Boot revolutionizes Spring Framework application development by offering an array of capabilities that streamline the process, bolster production readiness, and enhance the development experience.

Bad Practices

Spring Boot Exception Handling Best Practices

Conclusion

1. What is Spring Boot, and why should I use it?

2. How do I create a Spring Boot application?

3. What is the main class in a Spring Boot application?

4. What does the @SpringBootApplication annotation do?

5. How can you configure properties in a Spring Boot application?

6. How do you handle exceptions in Spring Boot?

7. What is Spring Boot Actuator and what are its benefits?

8. How can you enable and use Actuator endpoints in a Spring Boot application?

9. What are Spring Profiles and how do you use them?

10. How do you test a Spring Boot application?

11. How can you secure a Spring Boot application?

12. What is a Spring Boot Starter and why is it useful?

13. How can you configure a DataSource in Spring Boot?

14. What is Spring Boot DevTools and how does it enhance development?

15. How can you handle different environments in a Spring Boot application?

16. What are the differences between @Component, @Service, @Repository, and @Controller annotations?

17. How can you create a RESTful web service using Spring Boot?

18. What is Spring Boot CLI and how is it used?

19. How can you connect to a database using Spring Data JPA?

20. How can you use the H2 Database for development and testing in Spring Boot?

21. What is the purpose of @Autowired?

22. How can you customize the Spring Boot banner?

23. How can you create a custom starter in Spring Boot?

24. How do you run a Spring Boot application as a standalone jar?

25. What are the best practices for logging in Spring Boot?

26. How do you externalize configuration in Spring Boot?

27. How can you monitor Spring Boot applications?

28. How do you handle file uploads in Spring Boot?

29. What is the purpose of @ConfigurationProperties?

30. How do you schedule tasks in Spring Boot?

31. How can you use Spring Boot with Kotlin?

32. What is Spring WebFlux?

33. How do you enable CORS in Spring Boot?

34. How do you use Redis with Spring Boot?

35. What is Spring Cloud and how is it related to Spring Boot?

36. How do you implement caching in Spring Boot?

37. How can you send emails with Spring Boot?

38. What is @SpringBootTest?

39. How do you integrate Spring Boot with a front-end framework like Angular or React?

40. How do you configure Thymeleaf in Spring Boot?

41. What is the purpose of @SpringBootApplication?

42. How do you use CommandLineRunner in Spring Boot?

43. How do you connect to an external REST API using Spring Boot?

44. How do you implement pagination in Spring Boot?

45. How do you document a Spring Boot REST API?

46. How do you handle validation in Spring Boot?

47. How do you set up Spring Boot with Docker?

48. How do you deploy a Spring Boot application to AWS?

49. What is the difference between Spring Boot and Spring MVC?

50. How do you migrate a legacy application to Spring Boot?

Spring Boot Interview Questions: Conclusion

Related Articles:

Top 20 Microservices Interview Questions

Q1) What are Microservices?

Q2) What are the main features of Microservices?

Q3) What are the key parts of Microservices?

Q4) Explain the working of microservices?

Microservices Architecture:

Q5) What are the differences between Monolithic, SOA and Microservices Architecture?

Q6: What is Service Orchestration and Service Choreography in Microservices?

Q7) What is the role of an actuator in Spring Boot?

Q8) How to Customize Default Properties in Spring Boot Projects?

Q9) What is Cohesion and Coupling in Software Design?

Q10) What Defines Microservice Design?

Q11: What’s the Purpose of Spring Cloud Config and How Does It Work?

Q12) How Do Independent Microservices Communicate?

Q13) What is Domain-Driven Design (DDD)?

Q14). What is OAuth?

Q15) Why Reports and Dashboards Matter in Microservices?

Q16) What are Reactive Extensions in Microservices?

Q17) Types of Tests Commonly Used in Microservices?

Q18) What are Containers in Microservices?

Q19) The Core Role of Docker in Microservices?

Q20): What are tools used to aggregate microservices log files?

Table of Contents

Step 1: Understanding the Need

Step 2: What is Spring Boot Actuator?

4. What does the `@SpringBootApplication` annotation do?

16. What are the differences between `@Component`, `@Service`, `@Repository`, and `@Controller` annotations?

21. What is the purpose of `@Autowired`?

29. What is the purpose of `@ConfigurationProperties`?

38. What is `@SpringBootTest`?

41. What is the purpose of `@SpringBootApplication`?