One plus plus two compiles unexpectedly [duplicate]

Answer 1

Sometimes it's easier to see a problem using variables.

Your snippet could be rewritten as:

int a = 1;
int b = +2;
System.out.println(a + b); 

Now, you can easily see that the second + operator is used to indicate a positive value. You could also have written +1 + +2.

The - operator could be used to negate an expression.

+ and - are unary operators.