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Thread: That old JNA NoClassDefFound Error

  1. #1
    Junior Member
    Join Date
    Apr 2012
    Somerset, UK
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    Default That old JNA NoClassDefFound Error

    Hopefully someone can help as I have just about torn whats left of my hair out, and worn out my fingers searching google and various forums trying to find a solution ...

    I am putting together a home automation system based on the OpenZWave libraries, my system is Debian Linux, I am running a TomcatV7 Server to which I communicate with from an Android app, all this is working ok, all software is being built using Eclipse INDIGO. I have wrapped the OpenZWave library with a library called OpenZWrap which will have its methods exposed as extern 'C's for access by code running under tomcat. At the moment to simplify things I have removed all references to OpenZWave from the wrapper library and just have a simple no parameter test method which does a printf.

    // Test Code
    extern "C" void test1() {
    	printf(">>> test1 called <<<\n");

    The JNA interface is as follows:

    package com.birdsoft.birdhouse.control.interfaces;
    import com.sun.jna.Library;
    import com.sun.jna.Native;
    public interface OpenZWrapJNA extends Library {
    	OpenZWrapJNA INSTANCE = (OpenZWrapJNA) Native.loadLibrary("OpenZWrap", OpenZWrapJNA.class);
    	void test1();

    Ihave code which runs on startup of Tomcat which tries to use the JNA interface

    		// Test connection to OpenZWrap
    		OpenZWrapJNA jnaIf = OpenZWrapJNA.INSTANCE;

    When the 'OpenZWrapJNA jnaIf = OpenZWrapJNA.INSTANCE;' line above is executed when the server starts I get :

    EVERE: Exception sending context initialized event to listener instance of class com.birdsoft.birdhouse.control.startup.HardwareInt erfaceController
    java.lang.NoClassDefFoundError: com/sun/jna/NativeLibrary
    at com.birdsoft.birdhouse.control.startup.HardwareInt erfaceController.contextInitialized(HardwareInterf aceController.java:33)
    at org.apache.catalina.core.StandardContext.listenerS tart(StandardContext.java:4779)
    at org.apache.catalina.core.StandardContext.startInte rnal(StandardContext.java:5273)
    at org.apache.catalina.util.LifecycleBase.start(Lifec ycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild. call(ContainerBase.java:1566)
    at org.apache.catalina.core.ContainerBase$StartChild. call(ContainerBase.java:1556)
    at java.util.concurrent.FutureTask$Sync.innerRun(Futu reTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.jav a:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run Task(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
    Caused by: java.lang.ClassNotFoundException: com.sun.jna.NativeLibrary
    at org.apache.catalina.loader.WebappClassLoader.loadC lass(WebappClassLoader.java:1711)
    at org.apache.catalina.loader.WebappClassLoader.loadC lass(WebappClassLoader.java:1556)
    ... 11 more
    26-Apr-2012 11:57:54 org.apache.catalina.core.StandardContext startInternal
    SEVERE: Error listenerStart
    26-Apr-2012 11:57:54 org.apache.catalina.core.StandardContext startInternal
    SEVERE: Context [/BirdhouseControlService] startup failed due to previous errors
    Context Destroyed
    26-Apr-2012 11:57:54 org.apache.coyote.AbstractProtocol start
    INFO: Starting ProtocolHandler ["http-bio-8081"]

    In the TomcatServer project settings I have added the JavaNativeLibray JNA.jar and under this the location my OpenZWrap library.

    Any guidance gratefully received .. I thought I new java quite well but this has stumped me so far!

  2. #2
    Junior Member
    Join Date
    Apr 2012
    Somerset, UK
    Thanked 0 Times in 0 Posts

    Default Re: That old JNA NoClassDefFound Error

    Fixed the problem at the expense of the rest of my hair .. I added the jna.jar file to the classpath in the the service run configuration.

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