我对这个论坛有很大的怀疑，但是我很高兴感到惊讶；)对于那些使我重回正轨的人，我感到很荣幸。

我正在尝试使用JavaSpaces的快速实现(http://www.dancres.org/blitz/blitz_js.html)来实现http://today.java.net/pub/a/today/提供的ComputeFarm示例。 2005/04/21 / farm.html

内存中的示例工作正常，但是每当我尝试使用"闪电战"现成的实现时，都会出现以下错误：

(是com.sun.jini.mahalo.TxnMgrProxy在类路径中)

2008-09-24 09:57:37.316 ERROR [Thread-4] JavaSpaceComputeSpace 155     - Exception while taking task.
java.rmi.ServerException: RemoteException in server thread; nested exception is: 
    java.rmi.UnmarshalException: unmarshalling method/arguments; nested exception is: 
    java.lang.ClassNotFoundException: com.sun.jini.mahalo.TxnMgrProxy
    at net.jini.jeri.BasicInvocationDispatcher.dispatch(BasicInvocationDispatcher.java:644)
    at com.sun.jini.jeri.internal.runtime.ObjectTable.run(ObjectTable.java:597)
    at net.jini.export.ServerContext.doWithServerContext(ServerContext.java:103)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch0(ObjectTable.java:595)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.access0(ObjectTable.java:212)
    at com.sun.jini.jeri.internal.runtime.ObjectTable.run(ObjectTable.java:568)
    at com.sun.jini.start.AggregatePolicyProvider.run(AggregatePolicyProvider.java:527)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch(ObjectTable.java:565)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch(ObjectTable.java:540)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$RD.dispatch(ObjectTable.java:778)
    at net.jini.jeri.connection.ServerConnectionManager$Dispatcher.dispatch(ServerConnectionManager.java:148)
    at com.sun.jini.jeri.internal.mux.MuxServer.run(MuxServer.java:244)
    at com.sun.jini.start.AggregatePolicyProvider.run(AggregatePolicyProvider.java:513)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.jini.jeri.internal.mux.MuxServer.run(MuxServer.java:241)
    at com.sun.jini.thread.ThreadPool$Worker.run(ThreadPool.java:136)
    at java.lang.Thread.run(Thread.java:595)
    at com.sun.jini.jeri.internal.runtime.Util.__________EXCEPTION_RECEIVED_FROM_SERVER__________(Util.java:108)
    at com.sun.jini.jeri.internal.runtime.Util.exceptionReceivedFromServer(Util.java:101)
    at net.jini.jeri.BasicInvocationHandler.unmarshalThrow(BasicInvocationHandler.java:1303)
    at net.jini.jeri.BasicInvocationHandler.invokeRemoteMethodOnce(BasicInvocationHandler.java:832)
    at net.jini.jeri.BasicInvocationHandler.invokeRemoteMethod(BasicInvocationHandler.java:659)
    at net.jini.jeri.BasicInvocationHandler.invoke(BasicInvocationHandler.java:528)
    at $Proxy0.take(Unknown Source)
    at org.dancres.blitz.remote.BlitzProxy.take(BlitzProxy.java:157)
    at compute.impl.javaspaces.JavaSpaceComputeSpace.take(JavaSpaceComputeSpace.java:138)
    at example.squares.SquaresJob.collectResults(SquaresJob.java:47)
    at compute.impl.AbstractJobRunner$CollectThread.run(AbstractJobRunner.java:28)
Caused by: java.rmi.UnmarshalException: unmarshalling method/arguments; nested exception is: 
    java.lang.ClassNotFoundException: com.sun.jini.mahalo.TxnMgrProxy
    at net.jini.jeri.BasicInvocationDispatcher.dispatch(BasicInvocationDispatcher.java:619)
    at com.sun.jini.jeri.internal.runtime.ObjectTable.run(ObjectTable.java:597)
    at net.jini.export.ServerContext.doWithServerContext(ServerContext.java:103)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch0(ObjectTable.java:595)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.access0(ObjectTable.java:212)
    at com.sun.jini.jeri.internal.runtime.ObjectTable.run(ObjectTable.java:568)
    at com.sun.jini.start.AggregatePolicyProvider.run(AggregatePolicyProvider.java:527)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch(ObjectTable.java:565)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch(ObjectTable.java:540)
    at com.sun.jini.jeri.internal.runtime.ObjectTable$RD.dispatch(ObjectTable.java:778)
    at net.jini.jeri.connection.ServerConnectionManager$Dispatcher.dispatch(ServerConnectionManager.java:148)
    at com.sun.jini.jeri.internal.mux.MuxServer.run(MuxServer.java:244)
    at com.sun.jini.start.AggregatePolicyProvider.run(AggregatePolicyProvider.java:513)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.jini.jeri.internal.mux.MuxServer.run(MuxServer.java:241)
    at com.sun.jini.thread.ThreadPool$Worker.run(ThreadPool.java:136)
    at java.lang.Thread.run(Thread.java:595)
Caused by: java.lang.ClassNotFoundException: com.sun.jini.mahalo.TxnMgrProxy
    at java.net.URLClassLoader.run(URLClassLoader.java:200)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at net.jini.loader.pref.PreferredClassLoader.loadClass(PreferredClassLoader.java:922)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:242)
    at net.jini.loader.pref.PreferredClassProvider.loadClass(PreferredClassProvider.java:613)
    at java.rmi.server.RMIClassLoader.loadClass(RMIClassLoader.java:247)
    at net.jini.loader.ClassLoading.loadClass(ClassLoading.java:138)
    at net.jini.io.MarshalInputStream.resolveClass(MarshalInputStream.java:296)
    at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1544)
    at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1466)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1699)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1305)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1908)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1832)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1719)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1305)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:348)
    at com.sun.jini.jeri.internal.runtime.Util.unmarshalValue(Util.java:221)
    at net.jini.jeri.BasicInvocationDispatcher.unmarshalArguments(BasicInvocationDispatcher.java:1049)
    at net.jini.jeri.BasicInvocationDispatcher.dispatch(BasicInvocationDispatcher.java:599)
    ... 17 more

解决方案

好吧，Java Space服务器似乎找不到该类：

com.sun.jini.mahalo.TxnMgrProxy。

所以我想我们在启动服务器时只需将Mahalo(应根据以下内容包含在blitz发行版中：http://www.dancres.org/blitz/blitz_inst.html页)中。

如果此建议无济于事，请发布有关如何启动服务器的更多信息。

请注意我的原始帖子：是com.sun.jini.mahalo.TxnMgrProxy在类路径中

如果我们熟悉javap，则-如果指定完全限定的类名，它将确定它是否在类路径上。

这是我在运行javap com.sum.jini.mahalo.TxnMgrProxy时得到的结果：

C:\dev\jini\blitz>javap com.sun.jini.mahalo.TxnMgrProxy
Compiled from "TxnMgrProxy.java"
class com.sun.jini.mahalo.TxnMgrProxy extends java.lang.Object implements net.jini.core.transaction.server.TransactionManager,net.jini.admin.Admi
nistrable,java.io.Serializable,net.jini.id.ReferentUuid{
    final com.sun.jini.mahalo.TxnManager backend;
    final net.jini.id.Uuid proxyID;
    static com.sun.jini.mahalo.TxnMgrProxy create(com.sun.jini.mahalo.TxnManager, net.jini.id.Uuid);
    public net.jini.core.transaction.server.TransactionManager$Created create(long)       throws net.jini.core.lease.LeaseDeniedException, java.r
mi.RemoteException;
    public void join(long, net.jini.core.transaction.server.TransactionParticipant, long)       throws net.jini.core.transaction.UnknownTransacti
onException, net.jini.core.transaction.CannotJoinException, net.jini.core.transaction.server.CrashCountException, java.rmi.RemoteException;
    public int getState(long)       throws net.jini.core.transaction.UnknownTransactionException, java.rmi.RemoteException;
    public void commit(long)       throws net.jini.core.transaction.UnknownTransactionException, net.jini.core.transaction.CannotCommitException,
 java.rmi.RemoteException;
    public void commit(long, long)       throws net.jini.core.transaction.UnknownTransactionException, net.jini.core.transaction.CannotCommitExce
ption, net.jini.core.transaction.TimeoutExpiredException, java.rmi.RemoteException;
    public void abort(long)       throws net.jini.core.transaction.UnknownTransactionException, net.jini.core.transaction.CannotAbortException, j
ava.rmi.RemoteException;
    public void abort(long, long)       throws net.jini.core.transaction.UnknownTransactionException, net.jini.core.transaction.CannotAbortExcept
ion, net.jini.core.transaction.TimeoutExpiredException, java.rmi.RemoteException;
    public java.lang.Object getAdmin()       throws java.rmi.RemoteException;
    public net.jini.id.Uuid getReferentUuid();
    public int hashCode();
    public boolean equals(java.lang.Object);
    com.sun.jini.mahalo.TxnMgrProxy(com.sun.jini.mahalo.TxnManager, net.jini.id.Uuid, com.sun.jini.mahalo.TxnMgrProxy);
}

因此，com.sun.jini.mahalo.TxnMgrProxy包含在某个jar中，该jar包含在CLASSPATH环境变量中。

但是可能我们正在使用一些脚本来启动服务器。这很可能通过指定" -classpath"命令行开关来启动Java，该命令行开关优先于环境CLASSPATH变量。

http://java.sun.com/j2se/1.4.2/docs/tooldocs/windows/classpath.html

我们可以通过执行以下操作来模拟：

javap -classpath someUnknownJar.jar com.sun.jini.mahalo.TxnMgrProxy

……突然找不到该类了。因此，我们能否尝试找出启动客户端和服务器的Java VM的方式并提供完整的命令行。
(如果我们使用某种脚本，只需在java命令前面添加" echo ..."，然后将输出粘贴到此处)。

确保指定-Djava.security.policy = / wherever / policy.all和-Djava.security.manager =我们可能还必须运行RMI代码服务器。

这看起来像是RMI类加载问题。似乎服务器进程正在尝试解组传递给它的TxnMgrProxy对象(我不知道示例的细节，我有点想从堆栈跟踪中猜测)。该对象需要使用可在其中找到类定义的代码库进行注释。我们可能需要确保Mahalo是通过java.rmi.server.codebase属性启动的，该属性指向一个URL，可以在其中下载mahalo-dl.jar(或者某些保存类定义的JAR)。

即使JAR在本地可用，也可能不够用。 PreferredClassProvider(它埋在堆栈跟踪中)篡改了常规的Java类加载器委派方案，因此，即使该类在本地存在，它仍然希望通过代码库提取该定义。

这些都是很难解决的问题。希望我能找到答案附近的东西。祝你好运。