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Java™ Platform
Standard Ed. 8

Package org.omg.PortableServer

Provides classes and interfaces for making the server side of your applications portable across multivendor ORBs.

See: Description

Package org.omg.PortableServer Description


In Java, Portable Object Adaptor (POA)-based Dynamic Skeleton Interface (DSI) servants inherit from the standard DynamicImplementation class, which inherits from the Servant class. The native Servant type is defined by the PortableServer module for the POA. In Java, the Servant type is mapped to the Java org.omg.PortableServer.Servant class. It serves as the base class for all POA servant implementations and provides a number of methods that may be invoked by the application programmer, as well as methods which are invoked by the POA itself and may be overridden by the user to control aspects of servant behavior.

Package Specification

For a precise list of supported sections of official OMG specifications with which the Java[tm] Platform, Standard Edition 6 complies, see Official Specifications for CORBA support in Java[tm] SE 6.

POA-related Interfaces

The PortableServer module defines the following POA-related interfaces:

In addition, the POA defines the Servant native type.

Operations classes

Each of the interfaces listed above has an associated Operations interface. The Operations interface is generated by the idlj compiler and contains the method signatures for methods defined in its associated interface. The Operations interface can be accessed by both the client and the server, while its associated interface can only be called by the client.

Value Classes

Classes ending in the suffix PolicyValue provide the values used for the create_POA call, which sets the policy for the POA. See the sample code below for a demonstration. PolicyValue files include the following:

Helper Classes

Helper classes, which are generated for all user-defined types in an OMG IDL interface, supply static methods needed to manipulate those types. There is only one method in a helper class that an application programmer uses: the narrow method. Only Java interfaces mapped from IDL interfaces will have a helper class that includes a narrow method, so in the PortableServer package, only the following classes have a narrow method:

POA Classes

POA classes are used to implement the ServantActivator or ServantLocator.


The ForwardRequest exception indicates to the ORB that it is responsible for delivering the current request and subsequent ForwardRequest requests to the object denoted in the forward_reference member of the exception.

Interfaces Implemented by the Application Programmer

Most of what PortableServer does is transparent to the user. The result is that programmers will use only a few of the interfaces mentioned above. The remaining interfaces will be provided by the ORB implementation. The interfaces of interest to application programmers are the following:

Package org.omg.PortableServer.ServantLocatorPackage

This package supplies a CookieHolder class for passing the Cookie type as an out parameter. The CookieHolder class follows exactly the same pattern as the other holder classes for basic types.

Related Documentation

For an overview of Java IDL, please see:

  • Java IDL home page.

    Example Code

    Example Server Code

    import javax.naming.InitialContext;
    import javax.naming.Context;
    import javax.rmi.PortableRemoteObject ;
    import org.omg.PortableServer.*;
    import java.util.*;
    import org.omg.CORBA.*;
    import javax.rmi.CORBA.Stub;
    import javax.rmi.CORBA.Util;
    public class HelloServer {
        public HelloServer(String[] args) {
            try {
                Properties p = System.getProperties();
             //   p.put("org.omg.CORBA.ORBClass", "");
                ORB orb = ORB.init( args, p );
                POA rootPOA = (POA)orb.resolve_initial_references("RootPOA");
                Policy[] tpolicy = new Policy[3];
                tpolicy[0] = rootPOA.create_lifespan_policy(
                    LifespanPolicyValue.TRANSIENT );
                tpolicy[1] = rootPOA.create_request_processing_policy(
                    RequestProcessingPolicyValue.USE_ACTIVE_OBJECT_MAP_ONLY );
                tpolicy[2] = rootPOA.create_servant_retention_policy(
                POA tpoa = rootPOA.create_POA("MyTransientPOA", null, tpolicy);
                String  ObjectId = "MyObjectId";
                byte[] oid = ObjectId.getBytes();
                org.omg.CORBA.Object obj = tpoa.create_reference_with_id(oid,
                    new _HelloImpl_Tie()._all_interfaces(tpoa, oid)[0]);
                HelloInterface helloRef = (HelloInterface)PortableRemoteObject.narrow(
                    obj, HelloInterface.class );
                Context initialNamingContext = new InitialContext();
                initialNamingContext.rebind("HelloService", helloRef);
                System.out.println("Hello Server: Ready...");
             } catch (Exception e) {
                System.out.println("Trouble: " + e);
         public static void main(String args[]) {
             new HelloServer( args );

  • Since:
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    Java™ Platform
    Standard Ed. 8

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