J2EE.7.2 Interoperability Protocols


This specification requires that a J2EE product support a standard set of protocols and formats to ensure interoperability. The specification requires support for the following groups of protocols and formats:

  • Internet protocols

  • OMG protocols

  • RMI protocols

  • Data formats

Many of these protocols and formats are supported by J2SE and by the underlying operating system.

J2EE.7.2.1 Internet Protocols

Internet protocols define the standards by which the different pieces of the platform communicate with each other. The J2EE platform requires support for the following Internet protocols:

  • TCP/IP protocol family ” This is the core component of Internet communication. TCP/IP and UDP/IP are the standard transport protocols for the Internet.

  • HTTP 1.0 ” This is the core protocol of web communication. As with TCP/IP, HTTP 1.0 is supported by J2SE and the underlying operating system. A J2EE web container must be capable of advertising its HTTP services on the standard HTTP port, port 80.

  • SSL 3.0 ” SSL 3.0 (Secure Socket Layer) represents the security layer for web communication. It is available indirectly when using the https URL as opposed to the http URL. A J2EE web container must be capable of advertising its HTTPS service on the standard HTTPS port, port 443.

J2EE.7.2.2 OMG Protocols

This specification requires the J2EE platform to support the following Object Management Group (OMG) protocol:

  • IIOP (Internet Inter-ORB Protocol) ” Supported by Java IDL in J2SE and RMI-IIOP in J2EE. Java IDL provides standards-based interoperability and connectivity through the common object request broker architecture (CORBA). CORBA specifies the object request broker (ORB) which allows applications to communicate with each other regardless of location. This interoperability is delivered through IIOP, and is typically found in an intranet setting.

J2EE.7.2.3 RMI Protocols

This specification requires the J2EE platform to support the JRMP protocol, which is the Java technology-specific remote method invocation (RMI) protocol. JRMP is a distributed object model for the Java programming language. Distributed systems, which run in different address spaces and often on different hosts , must still be able to communicate with each other. RMI permits program-level objects in different address spaces to invoke remote objects using the semantics of the Java programming language object model.

Complete information on the JRMP specification can be found at http://java.sun.com/products/jdk/1.2/docs/guide/rmi.

J2EE.7.2.4 Data Formats

In addition to the protocols that allow communication between components, this specification also requires J2EE platform support for a number of data formats. These formats provide a definition for data that is exchanged between components .

The following data formats must be supported:

  • HTML 3.2 ” This represents the minimum web standard. It is not directly supported by J2EE APIs. However, it must be able to be displayed by J2EE web clients .

  • Image file formats ” The J2EE platform must support both GIF and JPEG images. Support for these formats is provided by the java.awt.image APIs (see the URL: http://java.sun.com/products/jdk/1.2/docs/api/java/awt/image/package-summary.html) and by J2EE web clients.

  • JAR files ” JAR (Java archive) files are the standard packaging format for Java technology-based application components, including the EJB JAR specialized format and the (to be specified) J2EE application jar package. JAR is a platform-independent file format that permits many files to be aggregated into one file. This allows multiple Java components to be bundled into one JAR file and downloaded to a browser in a single HTTP transaction. JAR file formats are supported by the java.util.jar and java.util.zip packages. For complete information on the JAR specification, see the URL: http://java.sun.com/products/jdk/1.2/docs/guide/jar.

  • Class file format ” The class file format is specified in the Java virtual machine specification. Each class file contains one Java programming language type ”either a class or an interface ”and consists of a stream of 8-bit bytes. For complete information on the class file format, see the URL: http://java.sun.com/docs/books/vmspec.



Java 2 Platform, Enterprise Edition. Platform and Component Specifications
Java 2 Platform, Enterprise Edition: Platform and Component Specifications
ISBN: 0201704560
EAN: 2147483647
Year: 2000
Pages: 399

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