Bitwise Operators (&, |, ^, ~) & Flag Manipulation

1Concept

Bitwise operators work on binary bit representations of integers. AND (&), OR (|), XOR (^), and NOT (~) enable low-level bit flag manipulation and performance optimizations.

2Architecture Diagram

Bitwise AND (&): 1010 & 1100 = 1000 (8)
Bitwise OR  (|): 1010 | 1100 = 1110 (14)
Bitwise XOR (^): 1010 ^ 1100 = 0110 (6)

3Code Example

public class BitwiseDemo {
    public static void main(String[] args) {
        int READ_PERMISSION = 1 << 0;  // 1 (0001)
        int WRITE_PERMISSION = 1 << 1; // 2 (0010)
        int EXEC_PERMISSION = 1 << 2;  // 4 (0100)

        int userPermissions = READ_PERMISSION | WRITE_PERMISSION;
        boolean canWrite = (userPermissions & WRITE_PERMISSION) != 0;
        System.out.println("User Permission Mask: " + userPermissions);
        System.out.println("Has Write Permission: " + canWrite);
    }
}

4Expected Output

User Permission Mask: 3
Has Write Permission: true

5Key Takeaways

• ✓Bitwise flags conserve memory by packing multiple boolean flags into a single integer.
• ✓Bitwise XOR (^) swaps two variables without temporary storage: a = a ^ b; b = a ^ b; a = a ^ b;.
• ✓Bitwise NOT (~) flips all binary bits.