awt Frame constructor not accepting naming of GraphicsConfiguration class

Question

I am just starting my Java endeavour and have just finished reading through the learning java sections on the oracle website. So I'm just looking through a few packages seeing what is what.

So I had a look at the awt package which I'm assuming is a graphics package of sort?

Anyhow, I have tried just creating a frame using the following:

import java.awt.*;

class WindowTest{
        public static void main(String[] args){
                Frame f = new Frame(GraphicsConfiguration gc);
                Rectangle bounds = gc.getBounds();
                f.setLocation(10 + bounds.x, 10 + bounds.y);
        }
}

I receive a compilation error when I try to compile, which is the following:

main.java:5: error: ')' expected
        Frame f = new Frame(GraphicsConfiguration gc);
                                                 ^
main.java:5: error: illegal start of expression
        Frame f = new Frame(GraphicsConfiguration gc);
                                                    ^
2 errors

I know I can't instantiate the GraphicsConfiguration as it's an abstract class and I cant initialise it with:

GraphicsConfiguration[] gc = GraphicsDevice.getConfiguration();

as the Frame does not accept GraphicsConfiguration[] as a constructor.

Any help would be appreciated, thanks.

Answer 1

When you call a method or constructor, you pass arguments - values - you're not declaring the parameters like you do when you declare the method or constructor.

So it should be something like:

GraphicsConfiguration gc = ...; // Whatever you need to get a value
Frame f = new Frame(gc);

Note that this is nothing to do with AWT specifically. It's just the basic syntax of calling a method or constructor. For example:

public class Test {
    public static void main(String[] args) {
        someMethod(10); // Fine; uses an integer literal
        int a = 10; 
        someMethod(a); // Fine; uses the value of a variable
        someMethod(int b); // Invalid syntax
    }

    public static void someMethod(int x) {
        System.out.println(x);
    }
}

In this specific case though, unless you have a particular GraphicsConfiguration you want to specify, just call the parameterless constructor:

Frame f = new Frame();