Java native interface problem

[Kristian Karl]

Hi,

Why does not the code below work...
I'm running int with j2re1.4.2_05, on a Windows 2000 box.

The output is:
Library loaded
java.lang.UnsatisfiedLinkError: MessageBoxA



public class ShowMsgBox extends Object {

static {
System.load("C:/WINNT/system32/USER32.DLL");
}

public static void main(String[] args) {
try
{
ShowMsgBox msg = new ShowMsgBox();
System.out.println( "Library loaded" );
msg.MessageBoxA( 0,
"Created by the MessageBox() Win32 func",
"Thinking in Java", 0);
}
catch (UnsatisfiedLinkError e)
{
System.out.println( e );
}
}
private native int MessageBoxA(int hwndOwner, String text,
String title, int fuStyle);
}

/Regards Kristian

 

[Tor Iver Wilhelmsen]

Why does not the code below work...

Because Java's JNI does not use COM methods directly.

java.lang.UnsatisfiedLinkError: MessageBoxA

JNI maps a Java native method to a C method with a particular syntax.

private native int MessageBoxA(int hwndOwner, String text,
String title, int fuStyle);

Read this:

http://java.sun.com/j2se/1.4.2/docs/guide/jni/index.html