why the answer is 15??

Question

class jkl
{
public static void main(String[] args)
{
int a=07;
int b=010;
System.out.println(a+b);
}
}

Answer 1

In Java integer numbers with a leading zero are interpreted as octal based numbers.
07 equals 7 in the decimal system
010 equals 8 in the decimal system

7+8 = 15