java active displays

To get the list of active displays in Java, you can use the GraphicsEnvironment class and the getLocalGraphicsEnvironment method to get the local graphics environment, and then use the getScreenDevices method to get an array of GraphicsDevice objects representing the active displays.

Here is an example of how you can get the list of active displays in Java:

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

// Get the local graphics environment
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();

// Get an array of GraphicsDevice objects representing the active displays
GraphicsDevice[] devices = ge.getScreenDevices();

// Print the number of active displays
System.out.println("Number of active displays: " + devices.length);

// Iterate through the active displays and print their information
for (int i = 0; i < devices.length; i++) {
    GraphicsDevice device = devices[i];
    System.out.println("Display " + (i+1) + ":");
    System.out.println("  Type: " + device.getType());
    System.out.println("  ID: " + device.getIDstring());
    System.out.println("  Width: " + device.getDisplayMode().getWidth());
    System.out.println("  Height: " + device.getDisplayMode().getHeight());
}

In this example, we use the getLocalGraphicsEnvironment method of the GraphicsEnvironment class to get the local graphics environment, which represents the graphics environment of the current Java virtual machine.

Then, we use the getScreenDevices method of the GraphicsEnvironment class to get an array of GraphicsDevice objects representing the active displays.

The GraphicsDevice class represents a display device, such as a monitor or a projector, and it provides methods to get information about the display, such as the type, the ID, the display mode, and so on.

We use the length property of the devices array to get the number of active displays, and then we use a for loop to iterate through the array and print the information about each display.

It is important to note that the GraphicsEnvironment and GraphicsDevice classes are part of the java.awt package, and they are not part of the core Java API.