Whats difference between this two: BigInteger.valueOf(10000) and BigInteger.valueOf(0010000)?

Question

I was working with one problem and came across this. What happen is:

when we use this: BigInteger.valueOf(10000) it gives value of 10000

But

when we use this BigInteger.valueOf(0010000) it gives value of 4096

Whats the difference between the two?

Answer 1

0010000 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.

Answer 2

The second one is integer in octal system, the first in decimal, that is the reason of the difference