How to Call JNA to VB.net ByRef String Function

[K-Full]

I want to call vb.net ByRef and String function from java.
vb.net dll is maked by UnmanagedExports.

//java
String[] str = {"testJavaWrited"};
String[] str2 = {"testJavaWrited2"};
final VbWrapper wr = (VbWrapper)Native.loadLibrary("vbtestlib", VbWrapper.class);
wr.test(str,str2);
System.out.println(str); // not printed
System.out.println(str2); // not printed

// jna mapping
public interface VbWrapper extends Library {
public int test(String[] str,String[] str2);
}

//vb.net
<DllExport("test", CallingConvention.StdCall)>
Function test(ByRef str As String, ByRef str2 As String) As Integer
MsgBox("test Called") ' printed
MsgBox(str) ' printed
str = "testStringWrited"
str2 = "testStringWrited2"
Return 0
End Function ' heap error

I need your help everybody.

http://stackoverflow.com/questions/41830352/how-to-call-jna-to-vb-net-byref-string-function

[3F]

:) You should use pointer to allocated string.

For example:

[DllExport]
public static int getStringArgs(ref IntPtr ptr)
{
    ptr = new UnmanagedString("Hello from .NET and Conari", UnmanagedString.SType.Ansi);    
    return 0;
}

[DllExport]
public static IntPtr getString()
{
    return new UnmanagedString("Hello from .NET and Conari", UnmanagedString.SType.Ansi);
}

Java:

public interface CAPI extends Library
{
    public PointerByReference getString();
    public int getStringArgs(LongByReference ptr); // see also Pointer etc.
}

CAPI l = Native.loadLibrary("DllExportAndJNA", CAPI.class);
...
LongByReference ptr = new LongByReference();
l.getStringArgs(ptr);
(new Pointer(ptr.getValue())).getString(0); // Hello from .NET and Conari

PointerByReference pbr = l.getString();
pbr.getPointer().getString(0); // Hello from .NET and Conari

etc.
In example above, the UnmanagedString is part of Conari engine, but of course you can use anything else, just for sample

anyway, do not forget deallocate all data from unmanaged memory !
And I recommend to use structures to aggregate all your states if you plan complex parameters between calling.

[K-Full]

Thank you very much 3F.
Your idea is good solution.
But, I wanted to use the standard library as much as possible.

Here is my vb code.

[DllExport]
public static int getStringArgs(ref IntPtr ptr)
{
    ptr = Marshal.StringToCoTaskMemAnsi("Hello from .NET")
    return 0;
}

[DllExport]
public static void freeString(ref IntPtr ptr)
{
    Marshal.ZeroFreeCoTaskMemAnsi(ptr)
    return;
}

Thank you for your help.