[Sun Microsystems] [ ] [ ] [Java]
Remote Objects for Java(tm)
These are the Early Access Releases of Java IDL (alpha1) and Java RMI
(alpha1), which are two of a number of Java interconnectivity products being
developed by JavaSoft.
Java IDL and Java RMI provide ways for transparently connecting Java clients
to network servers, using either the industry standard IDL Interface
Definition language, or a pure Java Remote Method Invocation (RMI)
mechanism.
If you're running a Java enabled browser, take a look at our Remote object
demos.
To download and use the early access distribution, see the download
instructions and the release notes.
Java Remote Method Invocation (RMI)
Description
The Java RMI system allows you to define a remote interface in Java by
defining a Java interface that inherits from the standard Java interface
sunw.rmi.RemoteObject.
This Java interface can then be compiled with a stub generator tool called
rmigen. This tool produces client and servers stubs that handle the details
of transmitting calls over the network.
Server programs can define remote objects in Java and then bind them to
URLs. Client applets can resolve the URLs to receive Java client objects.
When the applet invokes the client object, the call is automatically
transmitted to the Java object on the remote server.
Java RMI alpha1 is intended to provide application developers with a limited
Java RMI system to allow them to do evaluation and prototyping. See the
early access RMI design document for a description of limitations in this
early access release that will be removed in the final product system. Some
of the interfaces will change between RMI alpha1 and later releases. Also,
we guarantee that there will NOT be binary inter-operability with the actual
product release. A full roadmap and specification for the product RMI system
will be released in a few weeks.
Supported platforms
RMI alpha1 includes:
* Client runtimes that allow Java RMI clients to run either as
stand-alone Java applications, or as applets within Java enabled
browsers, such as Netscape 2.0.
* Server runtimes that allow Java applications to act as network servers
for RMI clients.
* A development tool (rmigen) that automatically generates stub code for
specific remote interfaces. This tool is written in Java and will run
on any java VM.
Availability
Java RMI alpha1 can be freely downloaded for evaluation and development use
until September 30th.
The client-side runtimes that allow Java applets to use Java RMI will be
bundled with a future release of the Java Developers Kit. The server-side
runtimes and the development tools will be sold as a separate product.
Java IDL
Description
The Java IDL system allows you to define remote interfaces in the IDL
interface definition language, which is an industry standard defined by the
Object Management Group (OMG).
These IDL definitions can then be compiled with the idlgen stub generator
tool to generate Java interface definitions and Java client and server
stubs. The mapping from IDL to Java is defined in the Java IDL language
mapping specification.
This allows a Java client to transparently invoke an IDL object that resides
on a remote server. Similarly, it allows a Java server to define objects
that can be transparently invoked from IDL clients.
Supported platforms
Java IDL alpha1 includes:
* Client runtimes that allow Java IDL clients to run either as
stand-alone Java applications, or as applets within Java enabled
browsers, such as Netscape 2.0.
* Server runtimes that allow Java applications to act as network servers
for IDL clients.
* A development tool (idlgen) that automatically generates stub code for
specific remote interfaces. Initially idlgen is only supported under
Solaris 2 on Sparc. We will add support for Windows 95 and Windows NT
soon.
Connecting to other ORBs
The Java IDL system is based on a portable Java ORB core which is structured
to make it easy to plug in new ORB protocols. The idlgen stub generator
produces stubs that are ORB independent, and which call into ORB specific
protocol modules for all data marshalling or other ORB specific operations.
This first early access release uses a lightweight TCP/IP based protocol
(the Door ORB) for connecting to Java servers. Javasoft is also developing
an IIOP protocol module to connect to other vendors's ORBs, and SunSoft is
developing a module to connect the Java IDL system directly to the NEO ORB.
We are also interested in working with third parties who want to develop
protocol modules for connecting the Java ORB core to other ORBs.
Availability
Java IDL alpha1 can be freely downloaded for evaluation and development use
until September 30th.
The client-side runtimes that allow Java applets to use Java IDL will be
bundled with a future release of the Java Developers Kit. The server-side
runtimes and the development tools will be sold as a separate product.
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