Is it possible to use Java to create dll?

Question

Want to create animation dll for Window XP Is it ok to create Java2d animation and export as dll??

Answer 1

Yes. You need to write code in C++ to start the JVM with the invocation interface to JNI, and call into it. However, you may find it difficult to create windows in this way that integrate seamlessly with your Windows environment application to display your animation. This is a rather advanced JNI usage, and I'd recommend reading the JNI book before even trying a little bit of it.

Answer 2

Actually, what Quentin said should work.
When you compile java to native with GCJ you first compile the .java files into platform specific .o (object) files. Presumably you would compile the .o files into a dll rather than an exe. GCJ also includes components like the garbage collector, and base java libraries. None of which require a JVM to run. The downer is that the dll would be huge. A simple "Hello World" app when compiled with GCJ is ~35MB, thanks to all the default libs and the garbage collector. Likewise your dll would be huge.

Answer 3

Yes, it is possible to generate DLLs from Java source code.

2 Methods I have used:

1. IKVM
2. Graal

IKVM is mature, but rather slow in runtime execution of the generated DLL.

Graal is fast, but early days and immature in the Windows environment. See https://openjdk.java.net/jeps/295 for further info.

There are other commercial options available as well.

Answer 4

I am pretty sure you can only create .Jar files from java not dlls

Answer 5

There are "bridges" that allow Java and non-Java code to call into one another. Depending on what you are trying to accomplish, these might be useful as you could write your Java code and then call into it from a C++ or C# DLL, depending on which language you are creating your DLL with, which will also determine what kind of bridge you need. I have never seen a freely provided bridge though. All the ones I've found when looking had to be purchased.

Answer 6

Well…

1. GCJ is available for Windows.
2. GCJ is part of GCC.
3. GCC can create dlls.

It might be possible to put that together to build DLLs using GCJ.