IDEs (IntelliJ, Eclipse)

What is an IDE?

An Integrated Development Environment (IDE) is a software application that provides comprehensive facilities for software development. IDEs combine multiple development tools into a single graphical interface, making coding more efficient and productive.

IntelliJ IDEA

IntelliJ IDEA, developed by JetBrains, is widely considered the most powerful and feature-rich Java IDE. It's the preferred choice for many professional Java developers.

Editions

• Community Edition - Free, open-source, covers Java SE development
• Ultimate Edition - Paid, includes web development, frameworks support, database tools

Key Features

// Smart Code Completion - IntelliJ predicts what you need
List<String> names = new Array  // Type "Array" and press Ctrl+Space
                                     // IntelliJ suggests ArrayList, Arrays, etc.

// Code Analysis - Real-time error detection
String name = null;
name.length();  // IntelliJ warns: "Method invocation may produce NullPointerException"

// Quick Fixes - Alt+Enter to fix issues
public void process(String data) {
    // Missing null check - Alt+Enter suggests adding validation
}

Essential Keyboard Shortcuts

Live Templates

// Type abbreviation and press Tab to expand

// "psvm" expands to:
public static void main(String[] args) {

}

// "sout" expands to:
System.out.println();

// "fori" expands to:
for (int i = 0; i < ; i++) {

}

// "iter" expands to enhanced for loop:
for (Object o : ) {

}

Eclipse IDE

Eclipse is a free, open-source IDE that has been a cornerstone of Java development for over two decades. It's highly extensible through its plugin architecture.

Eclipse Packages

• Eclipse IDE for Java Developers - Core Java development
• Eclipse IDE for Enterprise Java Developers - Jakarta EE, web development
• Eclipse IDE for Java and DSL Developers - Includes Xtext for DSLs

Key Features

// Content Assist (Ctrl+Space)
String message = "Hello";
message.  // Press Ctrl+Space to see all String methods

// Quick Fix (Ctrl+1)
// Hover over error/warning and press Ctrl+1 for suggestions

// Organize Imports (Ctrl+Shift+O)
// Automatically adds missing imports and removes unused ones

// Source menu (Alt+Shift+S)
// Generate getters, setters, constructors, toString, etc.

Essential Keyboard Shortcuts

Workspace and Projects

// Eclipse Workspace Structure
workspace/
├── .metadata/              # Eclipse settings
├── project-1/
│   ├── .project            # Project configuration
│   ├── .classpath          # Classpath settings
│   ├── .settings/          # Project-specific settings
│   └── src/
│       └── com/example/
│           └── Main.java
└── project-2/
    └── ...

Visual Studio Code

VS Code is a lightweight, cross-platform editor that can be transformed into a powerful Java IDE through extensions.

Essential Java Extensions

• Extension Pack for Java - Microsoft's comprehensive Java support
  • Language Support for Java (Red Hat)
  • Debugger for Java
  • Test Runner for Java
  • Maven for Java
  • Project Manager for Java
• Spring Boot Extension Pack - For Spring development
• Lombok Annotations Support - For Lombok users

VS Code Java Shortcuts

IDE Comparison

Debugging in IDEs

All major IDEs provide powerful debugging capabilities. Understanding debugging is essential for efficient development.

Common Debugging Actions

// Setting breakpoints - click in the gutter or use shortcuts

public void processOrder(Order order) {
    double total = 0;                    // Set breakpoint here

    for (Item item : order.getItems()) {
        double price = item.getPrice();   // Inspect variable values
        total += price;
    }

    applyDiscount(total);                // Step into this method (F7)

    order.setTotal(total);               // Step over (F8)
}

// Conditional breakpoints:
// Right-click breakpoint -> Add condition
// Example: item.getPrice() > 100

// Watches - monitor specific expressions
// Add watch: order.getItems().size()

Debug Shortcuts

Project Configuration

Setting Up JDK

// IntelliJ IDEA
// File -> Project Structure -> Project -> SDK
// Or: File -> Project Structure -> SDKs (to add new JDKs)

// Eclipse
// Window -> Preferences -> Java -> Installed JREs
// Project Properties -> Java Build Path -> Libraries

// VS Code
// settings.json:
{
    "java.configuration.runtimes": [
        {
            "name": "JavaSE-17",
            "path": "/path/to/jdk-17",
            "default": true
        },
        {
            "name": "JavaSE-21",
            "path": "/path/to/jdk-21"
        }
    ]
}

Import Maven/Gradle Project

// IntelliJ IDEA
// File -> Open -> Select pom.xml or build.gradle
// "Open as Project"

// Eclipse
// File -> Import -> Maven -> Existing Maven Projects
// Or: File -> Import -> Gradle -> Existing Gradle Project

// VS Code
// Open folder containing pom.xml
// Java extension auto-detects and imports

Productivity Tips

Code Generation Examples

// Generate constructor, getters, setters (Alt+Insert in IntelliJ)
public class User {
    private String name;
    private String email;
    private int age;

    // Generated constructor
    public User(String name, String email, int age) {
        this.name = name;
        this.email = email;
        this.age = age;
    }

    // Generated getter
    public String getName() {
        return name;
    }

    // Generated setter
    public void setName(String name) {
        this.name = name;
    }

    // Generated equals and hashCode
    @Override
    public boolean equals(Object o) { /* ... */ }

    @Override
    public int hashCode() { /* ... */ }

    // Generated toString
    @Override
    public String toString() {
        return "User{name='" + name + "', email='" + email + "', age=" + age + "}";
    }
}

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