It says the unary + operator makes a number positive, but numbers are positive anyway.
Now, I always thought the unary + was a promotion operator, making numbers take a larger space in memory, rather like casting a short to an int. This is what it says in the Java™ Language Specification:
15.15.3 Unary Plus Operator +
The type of the operand expression of the unary + operator must be a type that is convertible (�5.1.8) to a primitive numeric type, or a compile-time error occurs. Unary numeric promotion (�) is performed on the operand. The type of the unary plus expression is the promoted type of the operand. The result of the unary plus expression is not a variable, but a value, even if the result of the operand expression is a variable.
At run time, the value of the unary plus expression is the promoted value of the operand.
I can't find any recent threads about this topic.
Which is right? I think it's the Java Language Specification.
I think the Java Tutorial is just saying that the unary + denotes a positive number, but it's not really needed because this is the default anyway. (Note that it will not turn a negative value positive.)