Java Integer bitCount() Method

The bitCount() method of Integer class of java.lang package returns the count of set bits in a positive number. For negative numbers, it returns the count of set bits in its 2s complement form. This function is sometimes referred to as the population count. 

Syntax:

public static int bitCount(int n)

• Parameter: n: the value whose bits are to be counted
• Return: This method returns the count of set bits in a positive number. For negative numbers, it returns the count of set bits in its 2's complement form.

Example 1: To show the working of java.lang.Integer.bitCount() method. 

1010
2

• Time Complexity: O(1), because the number of bits is fixed (32 bits for int).
• Auxiliary Space: O(1), as no extra space proportional to the input is used.

Example 2:

Number of one-bits in num1: 2
Number of one-bits in num2: 30

• Time Complexity: O(1), because the number of bits is fixed (32 bits for int).
• Auxiliary Space: O(1), as no extra space proportional to the input is used.