How to output java full screen properly

Question

Now what I am doing in my program is that I am using setundecorated = true and MAXIMIZED_BOTH So it makes it go full screen and the display looks very nice, But the problem is that there are images (border) on the left and the right side of my screen and also a blue background. What happens is that in changing screens and resolutions these get disturbed and are not shown properly. Those grey patches come up again

History:

I have a java program which I wanted to always open in full screen; I was not able to find a way to do it properly so I had adjusted the minimum to (1370, 727) and maximum size. Thus, it started opening properly on my laptop, but when I changed my laptop's display to LCD, it started giving problems:

It opens in a smaller window:

If I then click on the maximize button, a grey area comes on the side and bottom (I wanted the items on screen to get stretched or center themselves):

And here for example, there is a grey patch at the bottom. Instead, I want the background to cover the whole screen.

Update 1 If I change to stretchable gridbaglayout, this is the code I used and what happens:

Menu.setExtendedState(MAXIMIZED_BOTH);
GridBagLayout gbl = new GridBagLayout();
Menu.setLayout(gbl);
JButton component = new JButton("1");
gbl.layoutContainer(Menu);
GridBagConstraints gbc = new GridBagConstraints();
gbc.fill = GridBagConstraints.NONE;
gbl.setConstraints(component, gbc);
Menu.add(component);
Menu.pack();
Menu.setVisible(true);

Question

1. How do I set "this" frame to setExtendedState(MAXIMIZED_BOTH) as I have done to others? (if I do this in main function, I get an error; even if I make a function for this and call it in main I get an error)

2. How do I get everything to stretch/rearrange themselves according to the extra grey space?

Update 2 My files in this project:

Update 3 This is the current file I am working on "FormTTS.java" Search for "MAXIMIZED_BOTH" in there and you will find the code I think you will want to check.

Answer 1

Usually, as far as games go, it's preferable to use full screen mode instead of using a maximized window. You can do this in Java by using:

GraphicsEnvironment gfxEnv = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice gfxDev = gfxEnv.getDefaultScreenDevice();

Window window = new GameWindow();
gfxDev.setFullScreenWindow(window);

If you still want to use a regular frame and center the content panel, you need to define some of the GridBagLayout constraints. It's impossible to tell which without out seeing the code for the rest of the components on that screen, but consider the following:

1. GridBagConstraints.fill
2. GridBagConstraints.anchor
3. GridBagConstraints.weightx
4. GridBagConstraints.weighty

And finally, regarding setting the screen to the largest size, it is already addressed here: Java JFrame Size according to screen resolution

Answer 2

I am also having same requirement as you have, below code works for me.

Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
setBounds(0,0,d.width,d.height); // i assume you have extended JFrame