java.lang.NoClassDefFoundError

Question

我不知道爲什麼這是有運行時錯誤，我已經搜索了這個問題，它說在編譯時可用的類在運行時不再可用。

這是代碼：

package examples.RMIShape; 
import java.rmi.*; 
import java.rmi.registry.LocateRegistry; 
import java.rmi.registry.Registry; 
//import java.rmi.server.UnicastRemoteObject; 

public class ShapeListServer { 
    public static void main(String args[]){ 
//  System.setSecurityManager(new RMISecurityManager()); 
     System.out.println("Main OK"); 
     try{ 
      ShapeList aShapelist = new ShapeListServant(); 
      System.out.println("After create"); 
      String registryURL = "rmi://localhost:" + "/ShapeList"; 
      startRegistry(); 
      Naming.rebind(registryURL, aShapelist); 
      System.out.println("ShapeList server ready"); 
     }catch(Exception e) { 
      System.out.println("ShapeList server main " + e.getMessage()); 
     } 
    } 

    // This method starts a RMI registry on the local host, if it 
    // does not already exists at the specified port number. 
    private static void startRegistry()throws RemoteException{ 
     Registry registry; 
     try { 
      registry = LocateRegistry.getRegistry(); 
      registry.list(); // This call will throw an exception 
      // if the registry does not already exist 
     } 
     catch (RemoteException e) { 
      // No valid registry at that port. 
      System.out.println ("RMI registry cannot be located at port " + Registry.REGISTRY_PORT); 
      registry = LocateRegistry.createRegistry(Registry.REGISTRY_PORT); 
      System.out.println("RMI registry created at port " + Registry.REGISTRY_PORT); 
     } 
    } // end startRegistry 
} 

Answer 1

Basicall java.lang.NoClassDefFoundError如果Java虛擬機或ClassLoader實例試圖在類的定義中加載拋出（作爲普通方法調用的一部分或作爲使用新表達式創建新實例的一部分）並且不能找到該類的定義。

以下鏈接將有所幫助。這個鏈接將指導你解決問題。

http://javarevisited.blogspot.in/2011/06/noclassdeffounderror-exception-in.html

http://javaeesupportpatterns.blogspot.in/2012/06/javalangnoclassdeffounderror-how-to.html

希望這將有助於

Answer 2

我用Google搜索這個問題，它說，在編譯期間是可利用的一類不再在運行時可用。

這是不正確的。這會導致ClassNotFoundException。這其中有幾個原因，但最常見的是文件中的類不是文件名和目錄層次所隱含的類。