output of System.out.println(0123)

System.out.println(0123)

It was a random meeting with System.out.println(0123)  and after the result, I was completely shocked.

   

    

I'm shocked because I was expecting the output of this statement is 123 as usual, but what I received is 83.

then I started to find out the reason behind that.

so what I found that if a number is leading with 0 as in my case it was 0123,

in this case, this number is interpreted as Octal, not Decimal.

Octal base(8).

0123 is treated as an octal based value of 123.

so in such a scenario, JVM  print the decimal corresponding value of  0123 which is 83.

example-

System.out.println(012):

(2 * 8 ^ 0) + (1 * 8 ^ 1) = 10

12₈ = 2*8⁰ +1*8¹ ---> 10

System.out.println(0123)

(3 * 8 ^ 0) + (2 * 8 ^ 1) + (1 * 8 ^ 2) = 83

123₈ = 3*8⁰ +2*8¹ +1*8² ---> 83