JNA sample program java.lang.NoClassDefFoundError

Question

I can compile this JNA code example (from step 2 of https://github.com/twall/jna/#getting_started ):

package com.sun.jna.examples;

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

/** Simple example of JNA interface mapping and usage. */
public class HelloWorld {

    // This is the standard, stable way of mapping, which supports extensive
    // customization and mapping of Java to native types.
    public interface CLibrary extends Library {
        CLibrary INSTANCE = (CLibrary)
            Native.loadLibrary((Platform.isWindows() ? "msvcrt" : "c"),
                               CLibrary.class);

        void printf(String format, Object... args);
    }

    public static void main(String[] args) {
        CLibrary.INSTANCE.printf("Hello, World\n");
        for (int i=0;i < args.length;i++) {
            CLibrary.INSTANCE.printf("Argument %d: %s\n", i, args[i]);
        }
    }
}

... using javac -classpath .:jna.jar -g HelloWorld.javawithout errors. (I downloaded jna.jar and placed it in the same directory as HelloWorld.java.)

But when I run it with java -classpath .:jna.jar HelloWorld, I get:

Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld (wrong name: com/sun/jna/examples/HelloWorld)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)

I get the same exception on Mac OS X and Linux.

How to do it?

Answer 1

This example (as with most Java classes) uses the packages:

package com.sun.jna.examples;

/ , javac/java (, , "com" ):

, examples. jna.jar :

/examples
 jna.jar
 /com
   /sun
      /jna
         /examples
           HelloWorld.java

:

javac -classpath .:jna.jar -g com/sun/jna/examples/HelloWorld.java

java -classpath .:jna.jar com.sun.jna.examples.HelloWorld

.

Answer 2

( , )

package com.sun.jna.examples;

, java ( ChssPly76s ).

, (, ) . , .

Answer 3

In Eclipse, under Java Build path > Order and exportselect export jna.jar.

Answer 4

Here is a good example (in Spanish), http://bdevmex.blogspot.mx/2013/01/comunicar-aplicaciones-mediante-jna.html I hope this can help you