Hi!

I've create simple application for test calling of dll functions and receive NullPointerException:

Exception in thread "main" java.lang.NullPointerException at java.lang.reflect.Array.getLength(Native Method) at com.sun.jna.Structure.getNativeSize(Structure.java:859) at com.sun.jna.Structure.getNativeSize(Structure.java:862) at com.sun.jna.Structure.calculateSize(Structure.java:764) at com.sun.jna.Structure.allocateMemory(Structure.java:194) at com.sun.jna.Structure.size(Structure.java:225) at com.sun.jna.Structure.useMemory(Structure.java:187) at com.sun.jna.Structure.useMemory(Structure.java:178) at com.sun.jna.Function.invoke(Function.java:324) at com.sun.jna.Function.invoke(Function.java:220) at com.sun.jna.Library$Handler.invoke(Library.java:204) at $Proxy0.GetTextList(Unknown Source) at SimpleTest.main(SimpleTest.java:33)

code of SimpleTest.java:

import com.sun.jna.Library; import com.sun.jna.Native; import com.sun.jna.Structure;

public class SimpleTest {

public static class ArrayClass { public byte[][] list = new byte[16][256]; }

public static class TextList extends Structure { public int count; public byte list[][] = new byte[16][128]; }

public interface mylib extends Library {

String GetText(); TextList GetTextList(); }

public static void main(String[] args) throws Exception {

String dllfile = "d:/testdll.dll"; mylib dll = (mylib) Native.loadLibrary(dllfile, mylib.class); TextList text = dll.GetTextList(); System.out.println(text.toString()); }

}

in DLL file -

TTextList * WINAPI GetTextList() { TextList.Count = 16; for(int i=0;i<16;i++) { strcpy(TextList.List[i], " This is test text in list"); } return &TextList; }

where: TTextList TextList;

struct TTextList{ int Count; char List[16][128]; };

Please, explain were is my (or your) mistake... Thanks

P.S. Win XP SP2, jdk1.5.0_06