CORBA, RMI and SOA

Web services is a Service Oriented Architecture implementation.

But, can we say that CORBA, RMI and the Java EE platform are also an implementation of SOA开发者_StackOverflow中文版?

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If you say that SOA means WS-* standards, then the answer is "no".

But if SOA means distributed components communicating using an agreed-upon protocol, then the answer is yes, you can think of CORBA, RMI, and Java EE as SOA. (My advice is to drop the "2" - it's been out of the picture for a long time. Please refer to it as Java EE unless you want to appear out-of-date.)

Even web services have at least two flavors: SOAP and REST. You might also include XML-RCP.

The difference in all cases is the choice of protocol.

SOAP uses its own XML request/response idiom over HTTP.

REST is straight HTTP - GET, POST, URL for every request.

CORBA uses an OMG standard protocol. Interoperability between ORBs, and different bindings for each language, used to be a big problem. It's been so long since I've used CORBA that I have no idea of the current state of the art. I don't know anyone who uses CORBA anymore. From my vantage point, it's a failed, dead technology.

RMI is the Java-only answer to CORBA. All endpoints must be implemented in Java and speak RMI.

Java EE uses RMI as the underpinnings of EJBs.

Simple and open win: that's why HTTP-based protocols are growing in popularity.

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yes. WS-* is one of the mostly used ways in which SOA is implemented.