“throw（e）”和“throw e”之间的区别？

Question

I came across this rethrown exception and am surprised that it even compiles.

} catch(SomeException e) {
    ...
    throw(e);
}

Is there any difference between this throw() and what is normally used?...

} catch(SomeException e) {
    ...
    throw e;
}

Any links to where this is documented or guidance on choosing one over the other?

Answer 1

Quite a few languages allow as many parenthesis around expressions as you want. Java is one of them. The following is perfectly valid code.

public class HelloWorld {
  public static void main(String[] args) {
    throw ((((new RuntimeException()))));
  }
}

So there's absolutely no difference, except that your source file is two bytes larger.

Answer 2

Functionally they are equivalent.

However, don't choose throw(e); , as someone might mistake it for a method call, and the very least will make someone unnecessarily wonder what it is that you're doing. Prefer the normal throw e; syntax for clarity.

Answer 3

Throw is an instruction to throw a "throwable" (usually an exception)

Think if it like a return statement

Public int get value() {
    return 3;
}

Is equlivilant of

Public int get value() {
    return (3);
}

It's the same with throwable.

In face they will complied to the exactly same thing.