Question

我试图使用rmi注册表来获取远程对象的引用。这是我的代码

void initialize_server () {
      //Look for other servers
    String[] otherservers = null;
    try {
        otherservers = Naming.list("//localhost:1099/");

    } catch (RemoteException e) {
        e.printStackTrace();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    }
    System.out.println("breakpoint");
    if (otherservers != null) {
        for (int i = 0; i < otherservers.length; i++) {
            System.out.println(otherservers[i]);

            IServer ref;
            try {
                ref = (IServer) Naming.lookup(otherservers[i]);
                model.addServer(ref);
            } catch (RemoteException e) {
                e.printStackTrace();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (NotBoundException e) {
                e.printStackTrace();
            }

        }
    }

直到这里它工作正常但它当然没有找到任何服务器，因为没有。所以，当我尝试在rmi上绑定一个像这样：

    String server_rmi="rmi://localhost/" + servername;
    try {
        Naming.rebind(server_rmi,this);
    } catch (RemoteException e) {
        e.printStackTrace();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    }
}

我收到一个永无止境的错误：

 java.rmi.ServerError: Error occurred in server thread; nested exception is: 
java.lang.UnsupportedClassVersionError: shared/IServer : Unsupported major.minor      version 52.0
at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:416)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:267)
at sun.rmi.transport.Transport$1.run(Transport.java:177)
at sun.rmi.transport.Transport$1.run(Transport.java:174)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:556)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:811)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:670)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
at       sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:275)
at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:252)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:378)
at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
at java.rmi.Naming.rebind(Naming.java:177)
at server.ServerController.initialize_server(ServerController.java:77)
at server.ServerController.<init>(ServerController.java:29)
at server.ServerStarter.main(ServerStarter.java:18)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

IServer界面是这样的：

package shared;

import java.rmi.Remote;
import java.rmi.RemoteException;
import java.util.Vector;

public interface IServer extends Remote {
Vector<IClient> Search (String search) throws RemoteException;
void SaveReference (IClient x) throws  RemoteException;
}

我使用ubuntu并且java -version命令返回此信息 java版＆＃34; 1.7.0_55＆＃34; Java（TM）SE运行时环境（版本1.7.0_55-b13） Java HotSpot（TM）64位服务器VM（内置24.55-b03，混合模式）

我已经失去了两个小时，而且我无法上班。我真的不知道该怎么做，请帮助我。

The error

Answer 1

java.lang.UnsupportedClassVersionError：shared / IServer：Unsupported major.minor版本52.0

这让我觉得您已经尝试使用比用于编译它的JDK更低版本的JRE来运行您的应用程序。让他们甚至摆脱这个错误

java error：UnsupportedClassVersionError

1 个答案: