Microsoft Java Virtual Machine

The Microsoft Java Virtual Machine (MSJVM) is a discontinued proprietary Java virtual machine from Microsoft. It was first made available for Internet Explorer 3 so that users could run Java applets when browsing on the World Wide Web. It was the fastest Windows-based implementation of a Java virtual machine for the first two years after its release.Sun Microsystems, the creator of Java, sued Microsoft in October 1997 for incompletely implementing the Java 1.1 standard. It was also named in the United States v. Microsoft antitrust civil actions, as an implementation of Microsoft's Embrace, extend and extinguish strategy. In 2001, Microsoft settled the lawsuit with Sun and discontinued its Java implementation.

The Microsoft JVM won the PC Magazine Editor's choice awards in 1997 and 1998 for best Java support. In 1998 a new release included the Java Native Interface which supplemented Microsoft's proprietary Raw Native Interface (RNI) and J/Direct. Microsoft claimed to have the fastest Java implementation for Windows, although IBM also made that claim in 1999 and beat the Microsoft and Sun virtual machines in the JavaWorld Volano test.

Microsoft's proprietary extensions to Java were used as evidence in the United States v. Microsoft antitrust civil actions.

A Memorandum of the United States in Support of Motion for Preliminary Injunction in the case of United States of America vs. Microsoft claimed that Microsoft wanted to kill Java in the marketplace.

In short, Microsoft feared and sought to impede the development of network effects that cross-platform technology like Netscape Navigator and Java might enjoy and use to challenge Microsoft's monopoly. Another internal Microsoft document indicates that the plan was not simply to blunt Java/browser cross-platform momentum, but to destroy the cross-platform threat entirely, with the "Strategic Objective" described as to "Kill cross-platform Java by grow[ing] the polluted Java market."

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