How to properly size your JFrame window according to the screen

The ideal dimension is to set the length and width with 2/3 the current monitor dimension. To retrieve the screen size in java, the java compiler has the getScreenSize() method of the Toolkit class. Here's an example:

//retrieve screen dimension
MonitorSize Dimension = Toolkit.getDefaultToolkit().getScreenSize(); 
int length = monitorsize.width * 2/3; 
int height = monitorsize.height * 2/3; 
//set the size of JFrame to 2/3 the screen size
frame.setSize(length, height); 

Output

You can change the size. For example, instead of 2/3 which would be  maybe  A little wider in a 12" screen but it never goes over the mark. When developing an application, always remember to follow this technique which is adaptable to all monitors