Assignment operators in Java are used to assign values to variables. The basic assignment operator is =, but there are several compound assignment operators that combine an arithmetic operation with assignment. Here’s a detailed explanation of assignment operators in Java.

Basic Assignment Operator (=)

The basic assignment operator is used to assign the value of the right operand to the left operand.

Example:

public class BasicAssignmentExample {
    public static void main(String[] args) {
        int a = 10; // Assigns 10 to variable a
        System.out.println("Value of a: " + a); // Output: Value of a: 10
    }
}

Compound Assignment Operators

Compound assignment operators are shorthand for performing an operation on a variable and then assigning the result back to that variable. They combine an arithmetic operation with the assignment operator.

1. Addition Assignment Operator (+=)

Adds the right operand to the left operand and assigns the result to the left operand.

Example:

public class AdditionAssignmentExample {
    public static void main(String[] args) {
        int a = 10;
        a += 5; // Equivalent to a = a + 5
        System.out.println("Value of a after += 5: " + a); // Output: Value of a after += 5: 15
    }
}

2. Subtraction Assignment Operator (-=)

Subtracts the right operand from the left operand and assigns the result to the left operand.

Example:

public class SubtractionAssignmentExample {
    public static void main(String[] args) {
        int a = 10;
        a -= 3; // Equivalent to a = a - 3
        System.out.println("Value of a after -= 3: " + a); // Output: Value of a after -= 3: 7
    }
}

3. Multiplication Assignment Operator (*=)

Multiplies the left operand by the right operand and assigns the result to the left operand.

Example:

public class MultiplicationAssignmentExample {
    public static void main(String[] args) {
        int a = 10;
        a *= 2; // Equivalent to a = a * 2
        System.out.println("Value of a after *= 2: " + a); // Output: Value of a after *= 2: 20
    }
}

4. Division Assignment Operator (/=)

Divides the left operand by the right operand and assigns the result to the left operand.

Example:

public class DivisionAssignmentExample {
    public static void main(String[] args) {
        int a = 20;
        a /= 4; // Equivalent to a = a / 4
        System.out.println("Value of a after /= 4: " + a); // Output: Value of a after /= 4: 5
    }
}

5. Modulus Assignment Operator (%=)

Calculates the remainder of the division of the left operand by the right operand and assigns the result to the left operand.

Example:

public class ModulusAssignmentExample {
    public static void main(String[] args) {
        int a = 10;
        a %= 3; // Equivalent to a = a % 3
        System.out.println("Value of a after %= 3: " + a); // Output: Value of a after %= 3: 1
    }
}

Summary

Assignment operators in Java are essential for assigning values to variables efficiently. The basic assignment operator allows you to set a variable's value, while compound assignment operators provide a concise way to update a variable using arithmetic operations. Understanding these operators is fundamental to writing effective and efficient Java code.