jni4net fails when calling .net from java using out and ref parameters

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jni4net is a great tool and is working for me in most cases, but fails when calling .NET from Java using out and ref parameters. Note that passing parameters by value and returning a single return value works fine. The following code is greatly simplified and is intended simply to illustrate the problem -- please don't answer that out and ref parameters should not be used in this case and just return the result instead.

Environment:

• Windows 7 (64-bit)


• java version "1.7.0_71"


• Java(TM) SE Runtime Environment (build 1.7.0_71-b14)


• Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)


• jni4net version 0.8.8.0

C# code to be called

// a simple object to be used as a parameter
public class Simple
{
    public int ID { get; set; }
    public string Name { get; set; }
}

// this is the .NET class to be called from Java
public static class MyDotNetClass
{
    public static void OutInt(out int value)
    {
        value = 999;
    }

    public static void RefInt(ref int value)
    {
        value = value + 1;
    }

    public static void OutString(out string value)
    {
        value = "out";
    }

    public static void RefString(ref string value)
    {
        value = value.ToUpper();
    }

}

Java code which invokes the C# methods via jni4net...

If you attempt any of the following:

Out<String> out1 = null;
MyDotNetClass.OutString(out1);

OR

Out<Integer> outInt = null;
MyDotNetClass.OutInt(outInt);

OR

Out<Simple> outSimple3 = null;
MyDotNetClass.OutSimple(outSimple3);

You get an error message such as:

A fatal error has been detected by the Java Runtime Environment:

EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x000000006e9098d6, pid=7164, tid=3968

JRE version: Java(TM) SE Runtime Environment (7.0_71-b14) (build 1.7.0_71-b14) Java VM: Java HotSpot(TM) 64-Bit Server VM (24.71-b01 mixed mode windows-amd64 compressed oops) Problematic frame: V [jvm.dll+0x1398d6]

Failed to write core dump. Minidumps are not enabled by default on client versions of Windows

An error report file with more information is saved as: C:\eclipse\workspace\myJavaTest\hs_err_pid7164.log

If you would like to submit a bug report, please visit:

http://ift.tt/19dgsTD

If you attempt the following:

Ref<String> refString1 = new Ref<String>("ref");
MyDotNetClass.RefString(refString1);

You get an error message such as:

Exception in thread "main" java.lang.IncompatibleClassChangeError at mydotnetassembly.MyDotNetClass.RefString(Native Method) at Program.main(Program.java:78) at net.sf.jni4net.jni.JNIEnv.ExceptionTest()(:0) at net.sf.jni4net.jni.JNIEnv.CallLongMethod()(:0) at net.sf.jni4net.inj.__IClrProxy.getClrHandle()(:0) at net.sf.jni4net.utils.Convertor.StrongJp2CString()(:0) at net.sf.jni4net.utils.Convertor.FullJ2C()(:0) at MyDotNetAssembly.__MyDotNetClass.RefString9()(:0)

However, if the ref parameter is an Integer or a simple C# object, it works:

Ref<Integer> refInt = new Ref<Integer>(1);
MyDotNetClass.RefInt(refInt);

Simple simple1 = new Simple();
simple1.setID(1);
simple1.setName("a");
Ref<Simple> refSimple1 = new Ref<Simple>(simple1);
MyDotNetClass.RefSimple(refSimple1);
id = simple1.getID();
name = simple1.getName();

Please let me know what needs to be done to successfully pass any out parameter or to successfully pass integers and strings as ref parameters. Thanks.

asked 1 min ago

Tabiona

1

jni4net fails when calling .net from java using out and ref parameters