If more than one screen is available, gets the size of each screen : GraphicsEnvironment « 2D Graphics « Java Tutorial

1. Java Tutorial
2. 2D Graphics
3. GraphicsEnvironment

import java.awt.DisplayMode;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;

public class Main {
  public static void main(String[] argv) throws Exception {

    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice[] gs = ge.getScreenDevices();

    for (int i = 0; i < gs.length; i++) {
      DisplayMode dm = gs[i].getDisplayMode();
      int screenWidth = dm.getWidth();
      int screenHeight = dm.getHeight();
    }

  }
}