Pad a binary String equal to zero (“0”) with leading zeros in Java

Question

Integer.toBinaryString(data)

gives me a binary String representation of my array data.

However I would like a simple way to add leading ze

Answer 1

This is what you asked for—padding is added only when the value is zero.

String s = (data == 0) ? String.format("%0" + len + 'd', 0) : Integer.toBinaryString(data);

If what you really want is for all binary values to be padded so that they are the same length, I use something like this:

String pad = String.format("%0" + len + 'd', 0);
String s = Integer.toBinaryString(data);
s = pad.substring(s.length()) + s;

Using String.format() directly would be the best, but it only supports decimal, hexadecimal, and octal, not binary.