What does the return keyword do in a void method in Java?

user_89211 0
Viewed 214826

I'm looking at a path finding tutorial and I noticed a return statement inside a void method (class PathTest, line 126):

if ((x < 0) || (y < 0) || (x >= map.getWidthInTiles()) || (y >= map.getHeightInTiles())) {
    return;
}

I'm a novice at Java. Can anyone tell me why it's there? As far as I knew, return inside a void method isn't allowed.

return void methods java
7 Answers

It just exits the method at that point. Once return is executed, the rest of the code won't be executed.

eg.

public void test(int n) {
    if (n == 1) {
        return; 
    }
    else if (n == 2) {
        doStuff();
        return;
    }
    doOtherStuff();
}

Note that the compiler is smart enough to tell you some code cannot be reached:

if (n == 3) {
    return;
    youWillGetAnError(); //compiler error here
}
user_851700

You can have return in a void method, you just can't return any value (as in return 5;), that's why they call it a void method. Some people always explicitly end void methods with a return statement, but it's not mandatory. It can be used to leave a function early, though:

void someFunct(int arg)
{
    if (arg == 0)
    {
        //Leave because this is a bad value
        return;
    }
    //Otherwise, do something
}
Pesto_239210

The keyword simply pops a frame from the call stack returning the control to the line following the function call.

user_903130

The Java language specification says you can have return with no expression if your method returns void.

John_695720

It exits the function and returns nothing.

Something like return 1; would be incorrect since it returns integer 1.

user_404430

It functions the same as a return for function with a specified parameter, except it returns nothing, as there is nothing to return and control is passed back to the calling method.

Chris_Ballance_15510
Related