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/*Error:LansinTVserver.MainFrame is not abstract and does not override abstract method sayHello(int,int) in LansinTVserver.RMIpublic class MainFrame  extends javax.swing.JFrame implements RMI {*/// Class MainFramepublic class MainFrame  extends javax.swing.JFrame implements RMI {...}//Class RMIabstract interface RMI extends Remote  {    int sayHello(int a, int b) throws RemoteException;}