Splash screen in java application.

The splash screen can be displayed at application startup, before the Java Virtual Machine (JVM) starts. The splash screen is displayed as an undecorated window containing an image. You can use GIF, JPEG, or PNG files for the image. Animation is supported for the GIF format, while transparency is supported both for GIF and PNG. The window is positioned at the center of the screen. The position on multi-monitor systems is not specified. It is platform and implementation dependent. The splash screen window is closed automatically as soon as the first window is displayed by Swing/AWT (may be also closed manually using the Java API, see below).

If your application is packaged in a jar file, you can use the "SplashScreen-Image" option in a manifest file to show a splash screen. Place the image in the jar archive and specify the path in the option. The path should not have a leading slash.
For example, in the manifest.mf file:

 Manifest-Version: 1.0
 Main-Class: Test
 SplashScreen-Image: filename.gif
 

If the Java implementation provides the command-line interface and you run your application by using the command line or a shortcut, use the Java application launcher option to show a splash screen. The Oracle reference implementation allows you to specify the splash screen image location with the -splash: option.
For example:

 java -splash:filename.gif Test
 

The command line interface has higher precedence over the manifest setting.

The splash screen will be displayed as faithfully as possible to present the whole splash screen image given the limitations of the target platform and display.

It is implied that the specified image is presented on the screen "as is", i.e. preserving the exact color values as specified in the image file. Under certain circumstances, though, the presented image may differ, e.g. when applying color dithering to present a 32 bits per pixel (bpp) image on a 16 or 8 bpp screen. The native platform display configuration may also affect the colors of the displayed image (e.g. color profiles, etc.)

The SplashScreen class provides the API for controlling the splash screen. This class may be used to close the splash screen, change the splash screen image, get the splash screen native window position/size, and paint in the splash screen. It cannot be used to create the splash screen. You should use the options provided by the Java implementation for that.

This class cannot be instantiated. Only a single instance of this class can exist, and it may be obtained by using the getSplashScreen() static method. In case the splash screen has not been created at application startup via the command line or manifest file option, the getSplashScreen method returns null.

Reference: https://docs.oracle.com/javase/7/docs/api/java/awt/SplashScreen.html