Immutable Class Example in Java

This example program shows how to create a custom or user defined Immutable class in Java.

What is Immutable in Java?

— An immutable class in Java is one whose content can not be changed once created.
— In Java there are many immutable classes like String, Boolean, Byte, Short, Integer, Long, etc.

// declare class as final
final class Immutable {

    // declare all variables as final
    private final int val1;
    private final String val2;

    // provide constructor to set the values
    public Immutable(int a, String s) {
        val1 = a;
        val2 = s;
    }

    // provide getters only
    public int getVal1() {
        return val1;
    }

    public String getVal2() {
        return val2;
    }
}

// declare class as final

final class Immutable {

// declare all variables as final

private final int val1;

private final String val2;

// provide constructor to set the values

public Immutable(int a, String s) {

val1 = a;

val2 = s;

}

// provide getters only

public int getVal1() {

return val1;

}

public String getVal2() {

return val2;

}

public class ImmutableClassDemo {
    public static void main(String[] args) {
        Immutable obj = new Immutable(10, "Immutable Class Example");
        System.out.println(obj.getVal1());
        System.out.println(obj.getVal2());
    }
}

public class ImmutableClassDemo {

public static void main(String[] args) {

Immutable obj = new Immutable(10, "Immutable Class Example");

System.out.println(obj.getVal1());

System.out.println(obj.getVal2());

}

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