CODEWITHSUNDEEP
javadlljar
Mudkip
Mudkip

Reputation: 373

Executing a .jar which makes use of native libraries (Java , .dll)

I have 2 different projects in java and I need to do the following with them: After a certain button from the program A is pressed, the program B is loaded and the program A is closed. Even though both projects have classes and dlls in common, I really do not want to merge everything into one single project.

I have done some searching and I found out that one possible solution would be to load the program B from a .jar using the following example of code:

btnMyButton.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        try {
            Runtime.getRuntime().exec("java.exe -jar \\url\\ProgramB.jar");
        } catch (IOException e1) {
                e1.printStackTrace();
        }
    }
});

I tried many variations of this (without the ".exe", for instance), and I made sure that the ProgramB.jar was in the same folder of its dlls, but nothing of this seemed to work.

So, I tried to open the ProgramB.jar directly (via Windows), and apparently everything was ok.

Later on, I tried to execute the ProgramB.jar via cmd (because I thought that the command "java.exe -jar \\url\\ProgramB.jar" could be executed on it). Even though I have set the library path (java -Djava.library.path=\\url\\ -jar \\url\\ProgramB.jar), an UnsatisfiedLinkError was thrown every time(X.dll->cannot find dependent libraries).

(Note: I won't be able to provide all the exception messages for a while because by the moment I do not have the program with me...)

Anyway, I am not sure exactly what I am doing wrong, but apparently there aren't any problems with the dlls implementation, since I was able to execute the program at least once. Any ideas are welcome.

Upvotes: 1

Views: 873

Answers (1)

Jimmysnn
Jimmysnn

Reputation: 593

The problem is java does not recognize the dll if is not in java.path

So first solution:

 put your dll in a java.path for example in windows C:\Windows\System32

Second solution

Set a new java variable which indicating the path where exist .dll file.

Also VMoption must be like: -Djava.library.path="path_to_dll"

This is not correct -Djava.library.path=path_to_dll\\dllname.dll

Upvotes: 1

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