RMI 绑定失败 "java.lang.ClassNotFoundException: rmitest.IRemote"

Question

我在将远程对象绑定到 RMI 注册表时遇到问题。我已将我的代码缩减为一个非常简单的示例，当我在我的计算机上测试它时可以正常工作 (Windows 10)。但是如果我在另一台计算机上启动它 (Windows 7)，当 registry.bind(id, remoteObject); 被调用时，我得到这个异常：

java.lang.ClassNotFoundException: 
rmitest.IRemote (no security manager: RMI class loader disabled)

我不需要 SecurityManager，因为所有 class 文件都在 jar 中，而且我不想使用动态代码加载功能。

为什么它会尝试加载一个安全管理器，为什么即使我定义了一个它也找不到？它可以在一台机器上运行但不能在另一台机器上运行的原因是什么？我认为代码没问题，肯定是配置问题，但我不确定到底是哪里配置错了。

这里是远程接口和远程对象实现，我在 Eclipse 中将其作为可运行的 Jar 导出为 rmitest.jar。

public interface IRemote extends Remote {
    void foo() throws RemoteException;
}

public class RemoteImpl extends UnicastRemoteObject implements IRemote {

    private static Registry     registry;

    public RemoteImpl() throws RemoteException {
        super();
    }

    public static void main(final String[] args) throws Exception {
        try {
            LocateRegistry.createRegistry(Registry.REGISTRY_PORT);
        } catch (final Exception e) {
            // already created
        }
        registry = LocateRegistry.getRegistry(Registry.REGISTRY_PORT);
        registry.bind(UUID.randomUUID().toString(), new RemoteImpl());
        System.out.println("Binding successful");
    }

    @Override
    public void foo() throws RemoteException {
        System.out.println("foo");
    }
}

这是完整的堆栈跟踪，它在调用 registry.bind 的行中抛出，并且在运行以下任一命令时完全相同： java -jar rmitest.jar 或
java -Djava.security.manager -Djava.security.policy=policy -jar rmitest.jar

很奇怪，显然在这两种情况下都需要安全管理器，但即使在第二种情况下也找不到。

Exception in thread "main" java.rmi.ServerException: RemoteException occurred in server thread; nested exception is: 
    java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
    java.lang.ClassNotFoundException: rmitest.IRemote (no security manager: RMI class loader disabled)
    at sun.rmi.server.UnicastServerRef.oldDispatch(Unknown Source)
    at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
    at sun.rmi.transport.Transport.run(Unknown Source)
    at sun.rmi.transport.Transport.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run6(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
    at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:276)
    at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:253)
    at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:379)
    at sun.rmi.registry.RegistryImpl_Stub.bind(Unknown Source)
    at rmitest.RemoteImpl.main(RemoteImpl.java:29)
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
    java.lang.ClassNotFoundException: rmitest.IRemote (no security manager: RMI class loader disabled)
    at sun.rmi.registry.RegistryImpl_Skel.dispatch(Unknown Source)
    at sun.rmi.server.UnicastServerRef.oldDispatch(Unknown Source)
    at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
    at sun.rmi.transport.Transport.run(Unknown Source)
    at sun.rmi.transport.Transport.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run6(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: rmitest.IRemote (no security manager: RMI class loader disabled)
    at sun.rmi.server.LoaderHandler.loadProxyClass(Unknown Source)
    at java.rmi.server.RMIClassLoader.loadProxyClass(Unknown Source)
    at java.rmi.server.RMIClassLoader.loadProxyClass(Unknown Source)
    at sun.rmi.server.MarshalInputStream.resolveProxyClass(Unknown Source)
    at java.io.ObjectInputStream.readProxyDesc(Unknown Source)
    at java.io.ObjectInputStream.readClassDesc(Unknown Source)
    at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.readObject(Unknown Source)
    ... 15 more

这是策略文件，应该允许所有内容：

grant {
  permission java.security.AllPermission;
};

Answer 1

问题出在其他 Java 进程运行上，它似乎干扰了注册表绑定。我不知道这个流氓进程到底做了什么，但杀死它解决了错误。不需要安全管理器，只需运行 jar 现在就可以像往常一样工作了。

Answer 2

问题是 'some other Java process' 提供了自己的注册表， 无法访问您的 CLASSPATH。你会发现如果你有比 createRegistry().

的空 catch 块更好的东西

RMI 绑定失败 "java.lang.ClassNotFoundException: rmitest.IRemote"

RMI binding fails with "java.lang.ClassNotFoundException: rmitest.IRemote"

java

rmi