java-idl

Java applications need to communicate with objects written in other languages (C++, Python, etc.) in a distributed environment. CORBA is the standard for cross-language distributed objects, but Java needs a way to participate in CORBA ecosystems.

Java IDL is Sun’s Java-based implementation of CORBA (Common Object Request Broker Architecture). It allows Java objects to integrate with other languages through CORBA services, making J2EE fully compatible with CORBA.

1. IDL (Interface Definition Language): Language-neutral way to define interfaces
2. Java IDL: Maps IDL interfaces to Java interfaces
3. CORBA ORB: Object Request Broker handles cross-language communication
4. IIOP protocol: Internet Inter-ORB Protocol for CORBA communication
5. J2EE compatibility: Full CORBA compatibility completes Java 2 Platform

Appendix B of the source discusses CORBA interoperability in detail.

• Cross-language: Java can talk to C++, Python, etc.
• CORBA standard: Implements CORBA 2.x specification
• IIOP protocol: Standard wire protocol for CORBA
• J2EE integration: Part of J2EE platform
• Full CORBA services: Leverages complete CORBA service set

• Built from: RMI — similar concept, Java-only vs cross-language
• Related: RMI-IIOP — RMI over IIOP protocol (used in J2EE)
• Builds into: Distributed Objects — Java IDL enables cross-language distributed objects
• Related: Java Platforms — Java IDL is part of J2EE

• Legacy technology: CORBA/IDL largely replaced by REST/JSON
• Complexity: CORBA has steep learning curve
• IIOP firewall issues: IIOP may be blocked by firewalls
• Modern alternative: Use REST or gRPC for cross-language communication