Sun Java System was a brand used by Sun Microsystems to market computer software. The Sun Java System brand superseded the Sun ONE brand in September 2003. There are two major suites under this brand, the Sun Java Enterprise System suite of infrastructure software, and the Sun Java Desktop System graphical user environment.

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Sun ONE was a brand under which Sun Microsystems marketed server software products from 2002 to 2003. Sun ONE stood for Sun Open Net Environment.

The Sun ONE brand was primarily used for products that resulted after the dissolution of Sun's alliance with Netscape Communications Corporation, which was sold under the brand name of iPlanet. The name was also applied to other Sun software products such as Sun ONE Studio 8 and Sun ONE Active Server Pages 4.0. Products included:

• Sun ONE Web Server
• Sun ONE Web Proxy Server
• Sun ONE Application Server
• Sun ONE Messaging Server
• Sun ONE Calendar Server
• Sun ONE Directory Server

Sun ONE was introduced on April 15, 2002, to supersede the iPlanet brand name, following the end of the Sun-Netscape alliance. Sun ONE itself was superseded on September 16, 2003, by the Sun Java System brand.^[1]

The Sun Java Enterprise System is itself broken into smaller suites, which include: