I was working with one problem and came across this. What happen is:
when we use this:
00100000 is an octal literal. This has nothing to do with
BigInteger - it's just Java integer literals (JLS 3.10.1):
System.out.println(10000); // 10000 System.out.println(0010000); // 4096
From the JLS:
A decimal numeral is either the single ASCII digit 0, representing the integer zero, or consists of an ASCII digit from 1 to 9 optionally followed by one or more ASCII digits from 0 to 9 interspersed with underscores, representing a positive integer.
An octal numeral consists of an ASCII digit 0 followed by one or more of the ASCII digits 0 through 7 interspersed with underscores, and can represent a positive, zero, or negative integer.