Run the example of jpf-core

[Isaac Ying]

hello
I wanted to run some examples in the src/examples. but an error issues every time. can u help?

[WARNING] unknown classpath element: /home/isaac/jpf/jpf-core/build/jpf-classes.jar
[WARNING] unknown classpath element: /home/isaac/jpf/jpf-symbc/build/jpf-symbc-classes.jar
[WARNING] orphan NativePeer method: java.lang.Class.initialize0()V
[WARNING] orphan NativePeer method: java.lang.Class.getByteArrayFromResourceStream(Ljava/lang/String;)[B
[WARNING] orphan NativePeer method: java.lang.Class.getResolvedName(Ljava/lang/String;)Ljava/lang/String;
[WARNING] orphan NativePeer method: java.lang.ClassLoader.getResource0(Ljava/lang/String;)Ljava/lang/String;
[WARNING] orphan NativePeer method: java.lang.ClassLoader.getResources0(Ljava/lang/String;)[Ljava/lang/String;
[WARNING] orphan NativePeer method: java.lang.ClassLoader.defineClass0(Ljava/lang/String;[BII)Ljava/lang/Class;
gov.nasa.jpf.vm.ClassInfoException: class not found: gov.nasa.jpf.BoxObjectCaches
    at gov.nasa.jpf.vm.ClassLoaderInfo.getResolvedClassInfo(ClassLoaderInfo.java:363)
    at gov.nasa.jpf.vm.SystemClassLoaderInfo.getResolvedClassInfo(SystemClassLoaderInfo.java:147)
    at gov.nasa.jpf.vm.VM.getStartupSystemClassInfos(VM.java:445)
    at gov.nasa.jpf.vm.VM.initializeMainThread(VM.java:564)
    at gov.nasa.jpf.vm.SingleProcessVM.initialize(SingleProcessVM.java:130)
    at gov.nasa.jpf.JPF.run(JPF.java:611)
    at gov.nasa.jpf.JPF.start(JPF.java:189)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at gov.nasa.jpf.tool.Run.call(Run.java:80)
    at gov.nasa.jpf.tool.RunJPF.main(RunJPF.java:116)
[SEVERE] cannot load system class gov.nasa.jpf.BoxObjectCaches