Java, unknown Bytes

Excuse me, I'm new to this and don't know how you caluculate the bytes.

public static int getPosSecondZero(int number){ if(number < 0){ return 0; } String binaryString = Integer.toBinaryString(number); char[] binaryCharArray = binaryString.toCharArray(); int count = 0; int idx = binaryCharArray.length; int length = binaryCharArray.length -1; while(count < 2){ idx--; if(binaryCharArray[idx] == '0'){ count++; } } return length-idx; }