How Java SplashScreen works? - java

I need to implement a SplashScreen in java, and i'm currently learning from How to Create a Splash Screen but there is paragraph that says
Fortunately, Java™ SE 6 provides a solution that allows the application to
display the splash screen much earlier, even before the virtual machine starts.
A Java application launcher is able to decode an image and display it in a
simple non-decorated window.
How is possible that java run the SplashScreen even if virtual machine starts if SplashScreen is a java class?

If you define the splash screen in your jar MANIFEST-file, it is loaded and displayed with native code before the Java VM is started. No need to load a class in that case. Later, you can get the SplashScreen instance to edit and/or close it.
Manifest entry:
SplashScreen-Image: images/splash.gif
Or command line option:
-splash:images/nnn.gif
Java Platform, Standard Edition (Java SE, formerly known as J2SE)
version 6, provides a solution that allows the application to show the
splash screen much earlier, even before the virtual machine starts.
Now, a Java application launcher is able to decode an image and
display it in a simple nondecorated window.
Source:
http://www.oracle.com/technetwork/articles/javase/splashscreen-135938.html

Related

How to locate elements on Java Swing Application for accessibility?

I'm trying to locate elements on my Java swing application window using Accessibility Insights for Windows. But, it is not identifying my own java swing windows application. However, it is working fine when I'm trying to locate elements on any other Windows App like, Calculator.
How do I inspect my own java swing application, just like any other Window App ?
Java Swing application is not like other Windows apps. Swing uses its own GUI controls and engine which runs completely within Java. To Windows, a Swing application seems like a single canvas in the size of a window; in other words it does not use any Windows API for controls like buttons, labels etc. This is why you are not seeing anything.
If you want to make your Java program accessible, you should follow the Java Accessibility Guide:
for Java 16 (PDF, dated 2021-03, latest version)
for Java 11 (PDF, dated 2020-12, LTS version)
for Java 8 (LTS version)
for Java 7

Can java AWT work without X11 or wayland?

I am setting up a home server on an old PC, but I am not using a server like apache, instead making a really basic one in java. I have got a extremely basic linux kernel compiled and working on it. But I want a gui along with my program. Is it possible for me to do it without installing X11 or wayland on my system?Note: I dont have anything on my system apart from the necessary java files.
You can run Java applications on headless mode on server environment.
From Oracle docs:
Headless mode is a system configuration in which the display device, keyboard, or mouse is lacking. Sounds unexpected, but actually you can perform different operations in this mode, even with graphic data.
It means you can run some AWT graphic stuff, even without X11, but obviously, not visible in your screen. As example, you can create graphics with java.awt.Canvas and save/export as a image. Available AWT classes in headless mode are: Canvas, Font, Image (and subclasses), Print classes and Beep.
See detailed info here: Headless Java SE

How can I call a Java application on background with keyboard keys?

I'm actually working on an screenshot saver on Windows, and i'd like to call to a method on the java application when I press a combination of keys to save the screen.
How can I call a method when the java application is not the "active" window? whether the main window is minimized or is running on background.
You're looking for a Hook in your keyboard for Windows. Note that hooking is highly relevant to the OS and your application may not be portable between different versions/editions of the OS. Still, you can do this using JNA as shown here: JNA Keyboard Hook in Windows or using a third party library like jnativehook.

Objective-C/Java interaction

I have some java code that I use on a windows machine that runs as a service and has a tray icon that I want to port to Mac OS X. From what I can tell there is no good way to make a menu bar icon using java, so I want to basically wrap my java code with objective-c so I can have a nice menu bar icon and still interact with the java code as I am able to when running the code on my windows box. Is there a good way to do this?
My java code makes web requests every so often so the main functionality I'm looking for is to start/stop the web client, as well as receive updates from the java code on the status of the web requests (more or less push notifications).
Thanks for your help everyone!
If all you're trying to do is get your application's icon displayed in the Dock & the Finder, you don't need to write an objective-C wrapper; all you need to do is bundle the Java code up in with the icons in an OS X "application bundle". See Apple's Java Deployment Guide
You might also want to look into the com.apple.eawt package (see questions/1319805/java-os-x-dock-menu), which provides some features to allow a Java app to appear more like a native OS X application to the user (for example, supporting drag-and-dropping a file to the application icon).

Launch another instance of Java app on Mac

I have a Mac Java app bundle that has problems opening an OpenGL window from a SWT dialog in a single process. It just doesn't work.
To solve this problem I would like to open a SWT dialog in one instance of the Java app and then have it launch another instance of itself with a parameter saying "this time open the OpenGL window". The part I don't know how to do is finding out what "itself" is on a Mac.
How can I do that?
You might be able to adapt this Swing based Launcher that uses
exec() to run programs in a separate JVM. If you need to include your own dynamic libraries, you might be able to use one of the relative path symbols described in man dyld under the heading Dynamic Library Loading.

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