Java 25 is Released! What are the Top 7 New Features with Code!

Java continues to evolve rapidly with its six-month release cycle, and Java 25, released on September 16, 2025, introduces numerous enhancements aimed at simplifying development, particularly for beginners.

For advanced users, Java 25 introduced powerful new tools. This version focuses on reducing boilerplate code, improving readability, and enhancing performance in concurrent scenarios.

In this blog, we'll dive into the key new features of Java 25, along with practical examples, so it makes more sense how they work. Whether you are a new programmer or an experienced developer, these updates make Java more accessible and efficient.

1. Instance Main Methods#

One of the most beginner-friendly changes in Java 25 is the support for instance main methods. Traditionally, the entry point for Java programs required a public static void main(String[] args) method. Now, you can omit public, static, and even the String[] args parameter if they're not needed. This simplifies writing quick test programs or scripts.

The JVM follows a specific order to locate the main method:

1. It first checks for the standard public static void main(String[] args).
2. If not found, it looks for public static void main().
3. If only an instance (non-static) main exists, it instantiates the class using a public no-arg constructor and calls the method.
4. If no valid main is found, it throws an error.

Example#

class Test {
    void main() {
        System.out.println("Hello, World!");
        System.out.println("This is Coding Shuttle");
    }
}

In this case, since there's no static main, the JVM creates an instance of Test and invokes the instance main() method.

2. Compact Source Files (Unnamed Classes)#

Java 25 introduces compact source files, where you don't need to explicitly declare a class. The compiler implicitly wraps your code in an unnamed, final class with a default no-arg constructor. This is perfect for simple scripts or learning exercises, as it lets you focus on logic without class declarations. However, a launchable main method is mandatory; otherwise, compilation fails.

You can define methods, fields, and use this within the file.

Example: Basic Hello World#

void main() {
    System.out.println("Hello, World");
}

Example: With Fields and Methods#

String msg = "Hello, World";

void main() {
    printMsg();
}

void printMsg() {
    System.out.println(msg);
}

This code runs as if it's inside an implicit class. The generated class is final and can't be extended or referenced by name.

3. Easier Console Input/Output Using The IO Helper Utility#

Console I/O in Java has historically been verbose, requiring classes like BufferedReader and exception handling. Java 25 addresses this with the new java.lang.IO class, providing static methods for simple printing and reading. Since it's in java.lang, no import is needed (though static imports can be used for convenience).

Key methods:

• IO.print("text"): Prints without a newline.
• IO.println("text"): Prints with a newline.
• IO.println(): Prints a blank line.
• IO.readln(): Reads a line of input.
• IO.readln("Prompt: "): Prompts and reads input.

Example: Printing#

import static java.lang.IO.*;

void main() {
    println("Hello, Coding Shuttle!");
}

Example: Input#

import static java.lang.IO.*;

void main() {
    var name = readln("What's your name? ");
    println("My Name is, " + name);
}

This eliminates boilerplate, making interactive programs easier for beginners.

4. Automatic Imports of Common APIs#

In compact source files, Java 25 automatically makes classes from commonly used packages in java.base (e.g., java.util, java.io) available without explicit imports. This reduces setup time for simple programs.

Example#

void main() {
    IO.println("Hello, World!");  // no import needed here
}

Here, IO is accessible directly, streamlining code in unnamed classes.

5. Flexible Constructor Bodies#

Constructors in prior Java versions required super(...) or this(...) calls as the first statement. Java 25 relaxes this, allowing statements before these calls in the "prologue" section. However, the prologue can't reference this or instance members (except to initialize uninitialized fields). The "epilogue" (after the call) follows normal rules.

Example#

class Parent {
    Parent() {
        IO.println("Parent Class Constructor");
    }
}

class Child extends Parent {
    Child() {
        IO.println("Child Class Constructor");
        super();
    }

    public static void main(String[] args) {
        new Child();
    }
}

Output:

Child Class Constructor
Parent Class Constructor

This feature enables pre-initialization logic, like logging or computations, before calling the superclass constructor.

6. Module Import Declarations#

For modular applications, Java 25 adds import module M;, which imports all packages exported by module M. This replaces multiple per-package imports, simplifying code when using libraries like java.sql.

Before#

import java.util.*;
import java.sql.*;
import java.nio.file.*;
import javax.sql.*;

public class DataProcessor {
    Path filePath = java.nio.file.Paths.get("data.txt");
    Map<String, Integer> dataMap = new HashMap<>();
    Connection dbConn = DriverManager.getConnection(...);
}

After#

import module java.base;
import module java.sql;

public class DataProcessor {
    Path filePath = Paths.get("data.txt");        // from java.base
    Map<String, Integer> dataMap = new HashMap<>(); // from java.base
    Connection dbConn = DriverManager.getConnection(...); // from java.sql
}

This reduces import clutter and improves maintainability.

7. Scoped Values#

Scoped values provide a lightweight alternative to ThreadLocal for sharing immutable data within a thread and its children, without explicit parameter passing. They're efficient, with a limited scope that ends when the binding block completes.

Declare a scoped value as static final ScopedValue<T>, bind it using ScopedValue.where(...).run(...) or .call(...), and access it via .get() inside the scope.

Example: Logger with Request ID#

import java.lang.ScopedValue;
import static java.lang.ScopedValue.where;

public class LoggerExample {

    // Define a ScopedValue for transaction ID
    static final ScopedValue<String> TRANSACTION_ID = ScopedValue.newInstance();

    public static void main(String[] args) {
        handleTransaction("TXN-001");
        handleTransaction("TXN-002");
    }

    static void handleTransaction(String id) {
        // Bind the transaction ID for this operation
        where(TRANSACTION_ID, id).run(() -> {
            execute();
            log("Transaction finished!");
        });
    }

    static void execute() {
        log("Executing operation...");
        storeData();
    }

    static void storeData() {
        log("Storing to database...");
    }

    static void log(String message) {
        // Access the bound transaction ID
        System.out.println("[" + TRANSACTION_ID.get() + "] " + message);
    }
}

Output:

[TXN-001] Executing operation...
[TXN-001] Storing to database...
[TXN-001] Transaction finished!
[TXN-002] Executing operation...
[TXN-002] Storing to database...
[TXN-002] Transaction finished!

Scoped values are ideal for contexts like logging, transactions, or security, offering better performance than ThreadLocal in deeply nested calls.

Conclusion#

Java 25 builds on Java's legacy by prioritising simplicity and productivity. Also, features like instance mains, compact files, and the IO class lower the entry barrier for new developers, while scoped values and module imports empower experienced ones.