Java JNA: JRE crashes after application completes

Question

I'm accessing a native lib with JNA. This is my first time ever working with JNA and I also don't have experience with c/c++. I was able to get the application to work and I get a correct result returned and displayed using System.out.println(). This is the last line of my code. The value is displayed in console and then Java crashes, eg. the dialog Java Platform SE binary has stopped working is displayed with option to close or debug.

The console then shows this:

Java Result: -1073741819

Windows Event viewer says 0xc0000005 which according to existing answers is a me

EDIT 5 21th August 2018:

This has still not been solved and now I'm looking into it again. What was solved was the issues with MemoryError when looping. Since I really need a solution now I also stop obfuscating the dll. AFAIK the supplier it out of business. They don't reply to questions and the web site is outdated.

My "documentation" comes from here

Here the current java code:

public interface CLogP extends StdCallLibrary {
    CLogP INSTANCE = (CLogP) Native.loadLibrary("BB-CLOGP", CLogP.class);
    NativeLong calcLogP(String smiles, FloatByReference logP, NativeLongByReference numContrb, HANDLEByReference contrib);
}

public static void main(String[] args) {

    //contrib can also be a PointerByReference, the behaviour is the same
    HANDLEByReference contrib = new HANDLEByReference();
    FloatByReference cLogP = new FloatByReference();
    NativeLongByReference numContrib = new NativeLongByReference();
    NativeLong err = CLogP.INSTANCE.calcLogP("c1ccccc1", cLogP, numContrib, contrib);
    System.out.println(err.intValue());
    System.out.println(cLogP.getValue());
    System.out.println(numContrib.getValue());
    //needs to be done after ever call to calcLogP
    //then no issue running in a loop
    Kernel32.INSTANCE.GlobalFree(contrib.getValue().getPointer());
    // Tried to free other variables, does not have any effect
    //Kernel32.INSTANCE.GlobalFree(cLogP.getPointer());
    //Kernel32.INSTANCE.GlobalFree(numContrib.getPointer());
}

I'm kind of lost. Above works with an outdated version of the dll but not with the newest one. What's going wrong? Would disassembling it help in any way?

OLD CODE and INFO, only partially relevant now:

My code:

public static void main(String[] args) {

    FloatByReference result = new FloatByReference();
    //EDIT: changed to NativeLongByReference as per suggested answer
    NativeLongByReference numContrib = new NativeLongByReference();     
    // This is a struct that needs to be passed by reference
    MyDll.PContribution.ByReference contrib = new MyDll.PContribution.ByReference();        
    NativeLong err = MyDll.INSTANCE.calcResult("myValue", result, numContrib, contrib);
    // I only care about result and not the other out-parameters
    System.out.println(result.getValue());
    //crash here
}

Defintion of the function in c:

typedef long (CALCRESULT)(const char*, float*, long*, HANDLE*);

What is going wrong? Do I need to perform some cleanup before the application terminates?

EDIT:

I can run the method call in a loop and it works. It only ever crashed when it terminates.

EDIT2:

As per comment here code for MyDll:

public interface MyDll extends Library {

    public static class PContribution extends Structure {
        public static class ByReference extends PContribution implements Structure.ByReference {

                public byte[] Class = new byte[10];
                public byte[] Type = new byte[6];
                public byte[] Description = new byte[40];
                public byte[] Comment = new byte[10];
                public float Value;
        }
            protected List getFieldOrder() {
                    return Arrays.asList(new String[] { "Class", "Type", "Description", "Comment", "Value" });
                }
}

    MyDll INSTANCE = (MyDll) Native.loadLibrary("MyDll", MyDll.class);

    NativeLong calcResult(String smi, FloatByReference result, NativeLongByReference numContrb, PContribution contrib);
}

Definition of the struct:

typedef struct {
    char Class[10];
    char Type[6];
    char Description[40];
    char Comment[10];
    float Value;
} PContribution;

EDIT 3:

Damn. I figured out that the available documentation is for an old version of the dll. Using the old dll, everything works. So now I need to get docs of new version from supplier.

EDIT 4:

It works with old dll but the app consistently crashes after 65533 iterations (calls). Each call uses exactly the same parameters.

java.lang.Error: Invalid memory access

at com.sun.jna.Native.invokeInt(Native Method)
at com.sun.jna.Function.invoke(Function.java:390)
at com.sun.jna.Function.invoke(Function.java:323)
at com.sun.jna.Library$Handler.invoke(Library.java:236)
at com.sun.proxy.$Proxy0.calcLogP(Unknown Source)

The whole point of the exercise is to be able to make thousands of calls quickly.

Java JNA: JRE crashes after application completes

Answers (1)

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