IntelliJ IDEA Tips and Tricks for Jakarta EE and Java 21 Development

IntelliJ IDEA offers an extensive array of powerful features that significantly enhance Jakarta EE and Java 21 development productivity. Let’s explore these capabilities in detail with comprehensive explanations and practical examples.

Jakarta EE Development Features

Namespace Migration Assistance – Automated Package Updates: IntelliJ provides sophisticated refactoring tools that automatically convert javax.* to jakarta.* packages, including:
- Comprehensive import statement updates that maintain code functionality while ensuring compatibility
- XML configuration file modifications that preserve application settings and deployment descriptors
- Build script adjustments that update dependencies and project configurations
- Dependency management updates that ensure all related libraries are properly referenced

Example of namespace migration:

// Before migration
import javax.servlet.http.HttpServlet;
import javax.persistence.EntityManager;

// After migration
import jakarta.servlet.http.HttpServlet;
import jakarta.persistence.EntityManager;

// Before migration

import javax.servlet.http.HttpServlet;

import javax.persistence.EntityManager;

// After migration

import jakarta.servlet.http.HttpServlet;

import jakarta.persistence.EntityManager;

Migration Preview: Before applying changes, IntelliJ shows a detailed preview of all modifications, including:
- Affected files and locations with line numbers and context
- Specific changes in each file with before/after comparisons
- Dependency updates required with version compatibility checks
- Potential conflicts to address with resolution suggestions

Example preview:

// Preview of changes in pom.xml
- <dependency>
-     <groupId>javax.servlet</groupId>
-     <artifactId>javax.servlet-api</artifactId>
-     <version>4.0.1</version>
- </dependency>
+ <dependency>
+     <groupId>jakarta.servlet</groupId>
+     <artifactId>jakarta.servlet-api</artifactId>
+     <version>5.0.0</version>
+ </dependency>

// Preview of changes in pom.xml

- <dependency>

- <groupId>javax.servlet</groupId>

- <artifactId>javax.servlet-api</artifactId>

- <version>4.0.1</version>

- </dependency>

+ <dependency>

+ <groupId>jakarta.servlet</groupId>

+ <artifactId>jakarta.servlet-api</artifactId>

+ <version>5.0.0</version>

+ </dependency>

Rollback Capability: If issues arise during migration, IntelliJ maintains a complete history of changes, allowing for:
- Selective rollback of specific modifications while preserving other changes
- Full migration reversal if needed, restoring all files to their original state
- Detailed change tracking with timestamps and modification details
- Comparison of before/after states to identify potential issues

Enterprise Framework Support – Spring Integration: Enhanced support for Spring Boot applications, including:
- Automatic configuration detection that identifies and validates Spring components
- Bean dependency visualization showing relationships between components
- Context-aware code completion that suggests relevant Spring components
- Spring-specific refactoring tools that maintain framework conventions

Example of Spring configuration:

@Configuration
public class AppConfig {
    @Bean
    public DataSource dataSource() {
        return DataSourceBuilder.create()
            .driverClassName("org.postgresql.Driver")
            .url("jdbc:postgresql://localhost:5432/mydb")
            .build();
    }
}

@Configuration

public class AppConfig {

@Bean

public DataSource dataSource() {

return DataSourceBuilder.create()

.driverClassName("org.postgresql.Driver")

.url("jdbc:postgresql://localhost:5432/mydb")

.build();

}

Hibernate Integration: Comprehensive JPA/Hibernate support featuring:
- Entity relationship mapping with visual representation
- Query optimization assistance with performance suggestions
- Database schema synchronization with migration tools
- JPQL/Criteria API support with code completion

Example of entity mapping:

@Entity
@Table(name = "employees")
public class Employee {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    private String name;

    @ManyToOne
    @JoinColumn(name = "department_id")
    private Department department;
}

@Entity

@Table(name = "employees")

public class Employee {

@Id

@GeneratedValue(strategy = GenerationType.IDENTITY)

private Long id;

@Column(nullable = false)

private String name;

@ManyToOne

@JoinColumn(name = "department_id")

private Department department;

}

Microservices Development: Dedicated tools for microservices architecture, including:
- Service discovery integration with Eureka/Consul support
- API gateway configuration with routing rules
- Distributed tracing with OpenTelemetry integration
- Container orchestration with Kubernetes support

Example of microservice configuration:

spring:
  cloud:
    gateway:
      routes:
        - id: employee-service
          uri: lb://employee-service
          predicates:
            - Path=/employees/**

spring:

cloud:

gateway:

routes:

- id: employee-service

uri: lb://employee-service

predicates:

- Path=/employees/**

Deployment and Testing – Server Integration: Seamless integration with popular Jakarta EE servers:
- Payara Server deployment with automatic configuration
- WildFly configuration with domain mode support
- Open Liberty support with feature management
- GlassFish deployment with cluster support

Example of server configuration:

<server>
    <featureManager>
        <feature>jakartaee-9.1</feature>
    </featureManager>
    <httpEndpoint id="defaultHttpEndpoint"
                 httpPort="9080"
                 httpsPort="9443"/>
</server>

<feature>jakartaee-9.1</feature>

</featureManager>

<httpEndpoint id="defaultHttpEndpoint"

httpPort="9080"

httpsPort="9443"/>

</server>

Testing Capabilities: Comprehensive testing features including:
- JUnit 5 support with Jupiter extensions
- Test coverage analysis with branch coverage
- Mocking assistance with Mockito integration
- Test optimization suggestions with performance metrics

Example of test configuration:

@ExtendWith(MockitoExtension.class)
class EmployeeServiceTest {
    @Mock
    private EmployeeRepository repository;

    @InjectMocks
    private EmployeeService service;

    @Test
    void testGetEmployee() {
        // Given
        Employee employee = new Employee(1L, "John Doe");
        when(repository.findById(1L)).thenReturn(Optional.of(employee));

        // When
        Employee result = service.getEmployee(1L);

        // Then
        assertEquals(employee, result);
        verify(repository).findById(1L);
    }
}

@ExtendWith(MockitoExtension.class)

class EmployeeServiceTest {

@Mock

private EmployeeRepository repository;

@InjectMocks

private EmployeeService service;

@Test

void testGetEmployee() {

// Given

Employee employee = new Employee(1L, "John Doe");

when(repository.findById(1L)).thenReturn(Optional.of(employee));

// When

Employee result = service.getEmployee(1L);

// Then

assertEquals(employee, result);

verify(repository).findById(1L);

}

Debugging Tools: Advanced debugging capabilities:
- Conditional breakpoints with complex conditions
- Expression evaluation with object graph inspection
- Thread debugging with deadlock detection
- Remote debugging with SSL support

Example of debugging configuration:

<configuration>
    <option

1 2	<configuration> <option

Java 21 Development Features

Language Features Support – Pattern Matching: Comprehensive support for Java 21’s pattern matching features:
- Switch expressions with type patterns
- Instanceof patterns with extraction
- Record patterns for structured data
- Code completion for pattern matching constructs

Example of pattern matching:

public String describe(Object obj) {
    return switch (obj) {
        case String s -> "String: " + s;
        case Integer i -> "Integer: " + i;
        case List<?> list -> "List with " + list.size() + " elements";
        default -> "Unknown type";
    };
}

public String describe(Object obj) {

return switch (obj) {

case String s -> "String: " + s;

case Integer i -> "Integer: " + i;

case List<?> list -> "List with " + list.size() + " elements";

default -> "Unknown type";

};

}

Sealed Classes: Enhanced support for sealed classes and interfaces:
- Permitted subclasses tracking with inheritance hierarchy
- Sealing status validation with compiler checks
- Inheritance hierarchy visualization with class diagram
- Code completion for permitted types with restrictions

Example of sealed classes:

public sealed class Shape permits Circle, Rectangle, Triangle {
    public abstract double area();
}

public final class Circle extends Shape {
    private final double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    @Override
    public double area() {
        return Math.PI * radius * radius;
    }
}

public sealed class Shape permits Circle, Rectangle, Triangle {

public abstract double area();

}

public final class Circle extends Shape {

private final double radius;

public Circle(double radius) {

this.radius = radius;

}

@Override

public double area() {

return Math.PI * radius * radius;

}

Virtual Threads: Dedicated support for virtual threads:
- Thread creation assistance with pool configuration
- Thread pool configuration with runtime settings
- Performance profiling with thread state analysis
- Thread lifecycle management with monitoring

Example of virtual threads:

public class VirtualThreadExample {
    public static void main(String[] args) {
        try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {
            executor.submit(() -> {
                // I/O-bound task
                processFile("data.txt");
            });
        }
    }
}

public class VirtualThreadExample {

public static void main(String[] args) {

try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {

executor.submit(() -> {

// I/O-bound task

processFile("data.txt");

});

}

Project Management

Dependency Management: Advanced dependency handling:

Maven/Gradle integration with automatic dependency resolution
Dependency conflict resolution with version analysis
Version compatibility checking with update suggestions
Transitive dependency management with exclusion handling

Example of dependency management:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.7.3</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-dependencies</artifactId>

<scope>import</scope>

</dependency>

</dependencies>

</dependencyManagement>

Code Analysis: Comprehensive code analysis features:

Code smell detection with severity levels
Performance optimization suggestions with metrics
Security vulnerability scanning with CWE references
Code quality metrics with trend analysis

Example of code analysis:

// Code smell: Method too long
public void processOrder(Order order) {
    // IntelliJ suggests splitting this into smaller methods
    validateOrder(order);
    updateInventory(order);
    sendConfirmation(order);
}

// Code smell: Method too long

public void processOrder(Order order) {

// IntelliJ suggests splitting this into smaller methods

validateOrder(order);

updateInventory(order);

sendConfirmation(order);

}

Version Control: Enhanced Git integration:

Branch management with remote tracking
Code review tools with inline comments
Commit message templates with conventions
Merge conflict resolution with visual tools

Example of Git workflow:

# IntelliJ Git workflow
git checkout -b feature/JEE-123
git commit -m "feat: Add Jakarta EE migration support"
git push origin feature/JEE-123

# IntelliJ Git workflow

git checkout -b feature/JEE-123

git commit -m "feat: Add Jakarta EE migration support"

git push origin feature/JEE-123

Productivity Features

Code Completion: Advanced code completion capabilities:

Smart completion with context awareness
Method parameter hints with documentation
Lambda expression completion with type inference
Framework-specific completions with configuration

Example of smart completion:

// IntelliJ suggests Spring components
@Autowired
private EmployeeRepository repository;

// IntelliJ provides method completions
repository.f// -> find, findAll, findById

// IntelliJ suggests Spring components

@Autowired

private EmployeeRepository repository;

// IntelliJ provides method completions

repository.f// -> find, findAll, findById

Live Templates: Customizable code templates:

Framework-specific templates with parameters
Project-specific snippets with variables
Parameterized templates with default values
Template sharing capabilities with team

Example of live template:

// Template: rest
@RestController
@RequestMapping("/api/$controllerName$")
public class $className$ {
    @Autowired
    private $serviceName$ service;

    @GetMapping
    public List<$entityClass$> getAll() {
        return service.findAll();
    }
}

// Template: rest

@RestController

@RequestMapping("/api/$controllerName$")

public class $className$ {

@Autowired

private $serviceName$ service;

@GetMapping

public List<$entityClass$> getAll() {

return service.findAll();

}

Code Navigation: Comprehensive code navigation features:

File structure view with dependency graph
Method navigation with call hierarchy
Usage tracking with reference search
Dependency navigation with import management

Example of navigation:

// IntelliJ shows navigation options
public class EmployeeController {
    // Alt + F7: Find usages
    // Ctrl + Click: Navigate to definition
    // Ctrl + Alt + B: Show implementation
    private final EmployeeService service;
}

// IntelliJ shows navigation options

public class EmployeeController {

// Alt + F7: Find usages

// Ctrl + Click: Navigate to definition

// Ctrl + Alt + B: Show implementation

private final EmployeeService service;

}

Code Refactoring: Advanced refactoring capabilities:

Safe rename operations with usage tracking
Method extraction with parameter optimization
Class restructuring with dependency management
Package reorganization with import fixing

Example of refactoring:

// Before refactoring
public void processOrder(Order order) {
    validate(order);
    save(order);
    notify(order);
}

// After refactoring
public void processOrder(Order order) {
    validateOrder(order);
    saveOrder(order);
    notifyCustomer(order);
}

// Before refactoring

public void processOrder(Order order) {

validate(order);

save(order);

notify(order);

}

// After refactoring

public void processOrder(Order order) {

validateOrder(order);

saveOrder(order);

notifyCustomer(order);

}

These features are most effective when used in combination with each other. For example, using code completion with live templates can significantly reduce boilerplate code, while the refactoring tools help maintain clean architecture as your project evolves. The key to maximum productivity is understanding how these features work together to support your development workflow.

Jakarta EE Development Features

Java 21 Development Features

Project Management

Productivity Features

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