reverse bit 32 unsigned integer - study code

reverseBit32UnsignedInteger5b.java

public class Solution {
	public long reverse(long A) {
	    long rev = 0;
	    
	    for (int i = 0; i < 32; i++) {
	        rev <<= 1;
	        if ((A & (1 << i)) != 0)
	            rev |= 1;
	    }
	    
	    return rev;
	    
	}
}