CORBA BAD_PARAM/201

Question

Hi
I'm having difficulty passing info from my server to my client; primitive data types are no problem, but am not successful in implementing arrays.
A video file is read into an array in the Server, and upon request from the Client, the Server attempts to pass the array to the Client
IDL
  typedef string VideoList [100];
  // i have also tried typedef sequence<string> videoList //
   VideoList getVideoList(); Server
    String [] video_list = new String[100];
    public String [] getVideoList()
      return video_list;
Client
  String [] client_video_list = new String [100];
  client_video_list = helloRef.getVideoList();
When the Client is executed, it fails on a CORBA.BAD_PARAM /201
ERROR : org.omg.CORBA.BAD_PARAM: vmcid: SUN minor code: 201 completed: Mayb
org.omg.CORBA.BAD_PARAM: vmcid: SUN minor code: 201 completed: Maybe
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Metho
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstru
orAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Delegatin
onstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
at java.lang.Class.newInstance0(Class.java:308)
at java.lang.Class.newInstance(Class.java:261)
at com.sun.corba.se.internal.iiop.messages.ReplyMessage_1_2.getSystemE
eption(ReplyMessage_1_2.java:90)
at com.sun.corba.se.internal.iiop.ClientResponseImpl.getSystemExceptio
ClientResponseImpl.java:105)
at com.sun.corba.se.internal.corba.ClientDelegate.invoke(ClientDelegat
java:314)
at org.omg.CORBA.portable.ObjectImpl._invoke(ObjectImpl.java:457)
at HelloApp1._HelloStub.getVideoList(_HelloStub.java:60)
at HelloClient.main(HelloClient.java:42)
Looking up the error code:
BAD_PARAM/201. vmcid: SUN minor code: 201 literally means "NULL_PARAM". This exception often occurs because a Java null was given to a write method such as write_string, write_octet_array, etc. You cannot return a Java null as the result of a Java method.
Any ideas ?

Answer 1

On the server side the video_list is not null .
Here are some snippets
Server
  // sayHello -  I call the getVideoList method from this method just to prove that the getVideoList returns an array
   public String sayHello()
      String aString = "from server";
      System.out.println("Well, hello to you too!");
      String [] array = getVideoList();
      System.out.println(array[0]);
      System.out.println("address of array is " + array);
      return aString;
   // getVideoList  - Prints out the 1st element and the address of the array
    public String [] getVideoList()
       System.out.println("1st element in Video List is " + video_list[0]);
       System.out.println("address of video_list is " + video_list);
       return video_list;
  // aVideo  -Returns a specific video from the array ; again to show that the array is not null
     public String aVideo(int x)
       System.out.println("A Video ?");
       System.out.println(video_list[x]);
       return video_list[x];
client
         System.out.println("Got this ..." + helloRef.sayHello());   
         String a_video = helloRef.aVideo(2);
         System.out.println("3rd video in client video list is ..." + a_video);
          String [] client_video_list = helloRef.getVideoList();            //  fails here
          String video = client_video_list[0];
          System.out.println("1st video in client video list is ..." + video);
server output
//  generated from helloRef.sayHello()
Well, hello to you too!
1st element in Video List is Harry Potter,1           
address of video_list is [Ljava.lang.String;@872380
Harry Potter,1
address of array is [Ljava.lang.String;@872380
//  generated from helloRef.aVideo(2)
A Video ?
Start Trek,1
//  generated from helloRef.getVideoList()
1st element in Video List is Harry Potter,1
address of video_list is [Ljava.lang.String;@872380
client output
//  generated from helloRef.sayHello()
Got this ...from server
//  generated from helloRef.aVideo(2)
3rd video in client video list is ...Start Trek,1
//  generated from helloRef.getVideoList()
ERROR : org.omg.CORBA.BAD_PARAM:   vmcid: SUN  minor code: 201 completed: Maybe
org.omg.CORBA.BAD_PARAM:   vmcid: SUN  minor code: 201 completed: Maybe
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct
orAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC
onstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
        at java.lang.Class.newInstance0(Class.java:308)
        at java.lang.Class.newInstance(Class.java:261)
        at com.sun.corba.se.internal.iiop.messages.ReplyMessage_1_2.getSystemExc
eption(ReplyMessage_1_2.java:90)
        at com.sun.corba.se.internal.iiop.ClientResponseImpl.getSystemException(
ClientResponseImpl.java:105)
        at com.sun.corba.se.internal.corba.ClientDelegate.invoke(ClientDelegate.
java:314)
        at org.omg.CORBA.portable.ObjectImpl._invoke(ObjectImpl.java:457)
        at HelloApp1._HelloStub.getVideoList(_HelloStub.java:82)
        at HelloClient.main(HelloClient.java:45)So you can see from all this that the video_list is not null ;
Once again the IDL is as follows:
  module HelloApp1
     typedef sequence<string> videoList;
    // Interface to a hello object
    interface Hello
      string sayHello();
      void sayGoodNight();
      string aVideo(in long x );
      videoList getVideoList();
};Any ideas ?