Bitwise Operators in Java

Bitwise operators in Java are used to perform operations directly on the binary representation (bits) of integer values. Instead of working on whole numbers, these operators manipulate data bit by bit, enabling fast and efficient low-level operations.

• Bitwise operators work only with integer data types such as byte, short, int, long, and char
• They are commonly used in performance optimization, system programming, and competitive coding

What Are Bitwise Operators?

Bitwise operators operate on each bit of a number individually according to the specified operation. When a bitwise operation is applied, the corresponding bits of the operands are evaluated and combined to produce a result.

Below are the main bitwise operators available in Java:

Now, let's look at each one of the bitwise operators in Java: 

1. Bitwise AND (&)

This operator is a binary operator, denoted by '&.' It returns bit by bit AND of input values, i.e., if both bits are 1, it gives 1, else it shows 0. 

Example:

a = 5 = 0101 (In Binary)
b = 7 = 0111 (In Binary)

Bitwise AND Operation of 5 and 7
0101
& 0111
________
0101 = 5 (In decimal)

2. Bitwise OR (|) 

This operator is a binary operator, denoted by '|'. It returns bit by bit OR of input values, i.e., if either of the bits is 1, it gives 1, else it shows 0. 

Example:

a = 5 = 0101 (In Binary)
b = 7 = 0111 (In Binary)

Bitwise OR Operation of 5 and 7
0101
| 0111
________
0111 = 7 (In decimal)

3. Bitwise XOR (^) 

This operator is a binary operator, denoted by '^.' It returns bit by bit XOR of input values, i.e., if corresponding bits are different, it gives 1, else it shows 0. 

Example:

a = 5 = 0101 (In Binary)
b = 7 = 0111 (In Binary)

Bitwise XOR Operation of 5 and 7
0101
^ 0111
________
0010 = 2 (In decimal)

4. Bitwise Complement (~)

This operator is a unary operator, denoted by '~.' It returns the one's complement representation of the input value, i.e., with all bits inverted, which means it makes every 0 to 1, and every 1 to 0. 

Example:

a = 5 = 0101 (In Binary)

Bitwise Complement Operation of 5 in java (8 bits)

~ 00000101
________
11111010 = -6 (In decimal)

Explanation: The bitwise complement of 5 is 11111010, which in two's complement format represents -6. The two's complement of N is ~N + 1, so ~5 results in -6.

Twist in Bitwise Complement Operator in Java

The bitwise complement of 5 is 246 and The 2's complement of 246 is -6. Hence, the output is -6 instead of 246.

bitwise complement of N = ~N (represented in 2's complement form)
2'complement of ~N = -(~(~N)+1) = -(N+1).

For Example: The 2's complement of a number is equal to the complement of that number + 1 .

Illustration: Here is a Java program demonstrating all bitwise operators.

public class Geeks {
    public static void main(String[] args)
    {
        // Initial values
        int a = 5;
        int b = 7;

        // bitwise and
        // 0101 & 0111=0101 = 5
        System.out.println("a&b = " + (a & b));

        // bitwise or
        // 0101 | 0111=0111 = 7
        System.out.println("a|b = " + (a | b));

        // bitwise xor
        // 0101 ^ 0111=0010 = 2
        System.out.println("a^b = " + (a ^ b));

        // bitwise not
        // ~00000000 00000000 00000000 00000101=11111111 11111111 11111111 11111010
        // will give 2's complement (32 bit) of 5 = -6
        System.out.println("~a = " + ~a);

        // can also be combined with
        // assignment operator to provide shorthand
        // assignment
        // a=a&b
        a &= b;
        System.out.println("a= " + a);
    }
}

a&b = 5
a|b = 7
a^b = 2
~a = -6
a= 5

Bitwise Operators with Binary Output 

Example: Here is the Java program that shows the bitwise operations using binary strings.

class Geeks {
    public static void main (String[] args) {
      
        String binary[]={
          "0000","0001","0010","0011","0100","0101",
          "0110","0111","1000","1001","1010",
          "1011","1100","1101","1110","1111"
        };
      
      // initializing the values of a and b 
      int a=3; // 0+2+1 or 0011 in binary
      int b=6; // 4+2+0 or 0110 in binary
      
      // bitwise or
      int c= a | b;
      
      // bitwise and
      int d= a & b;
      
      // bitwise xor
      int e= a ^ b;
      
      // bitwise not
      int f= (~a & b)|(a &~b);
      int g= ~a & 0x0f;
      
      
      System.out.println(" a= "+binary[a]);
      System.out.println(" b= "+binary[b]);
      System.out.println(" a|b= "+binary[c]);
      System.out.println(" a&b= "+binary[d]);
      System.out.println(" a^b= "+binary[e]);
      System.out.println("~a & b|a&~b= "+binary[f]);
      System.out.println("~a= "+binary[g]);
    }
}

 a= 0011
 b= 0110
 a|b= 0111
 a&b= 0010
 a^b= 0101
~a & b|a&~b= 0101
~a= 1100

Bit-Shift Operators (Shift Operators) 

Shift operators are used to shift the bits of a number left or right, thereby multiplying or dividing the number by two, respectively. They can be used when we have to multiply or divide a number by two. 

Syntax: 

number shift_op number_of_places_to_shift;

Types of Shift Operators

Shift Operators are further divided into 3 types. These are:

1. Signed Right shift operator (>>)
2. Unsigned Right shift operator (>>>)
3. Left shift operator(<<)

Note: For more detail about the Shift Operators in Java, refer Shift Operator in Java.

Example: Program to Implement all Bitwise Operators in Java for User Input

import java.util.Scanner;

public class Geeks {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.print("Enter first number: ");
        int num1 = input.nextInt();

        System.out.print("Enter second number: ");
        int num2 = input.nextInt();

        System.out.println("Bitwise AND: " + (num1 & num2));
        System.out.println("Bitwise OR: " + (num1 | num2));
        System.out.println("Bitwise XOR: " + (num1 ^ num2));
        System.out.println("Bitwise NOT: " + (~num1));
        System.out.println("Bitwise Left Shift: " + (num1 << 2));
        System.out.println("Bitwise Right Shift: " + (num1 >> 2));
        System.out.println("Bitwise Unsigned Right Shift: " + (num1 >>> 2));

        input.close();
    }
}

Input:

Enter first number: 4
Enter second number: 8

Output:

Bitwise AND: 0
Bitwise OR: 12
Bitwise XOR: 12
Bitwise NOT: -5
Bitwise Left Shift: 16
Bitwise Right Shift: 1
Bitwise Unsigned Right Shift: 1

Explanation:

This program prompts the user to enter two numbers, num1 and num2. It then performs the following bitwise operations using the &, |, ^, ~, <<, >>, and >>> operators: