How to get 0-padded binary representation of an integer in java?

Question

for example, for 1, 2, 128, 256 the output can be (16 digits):

0000000000000001
0000000000000010
0000000010000000
0000000100000000

Answer 1

A simpler version of user3608934's idea "This is an old trick, create a string with 16 0's then append the trimmed binary string you got ":

private String toBinaryString32(int i) {
    String binaryWithOutLeading0 = Integer.toBinaryString(i);
    return "00000000000000000000000000000000"
            .substring(binaryWithOutLeading0.length())
            + binaryWithOutLeading0;
}