Many Java programmers across the globe prefer to use Java in its original form. Having put their efforts into learning Java APIs, they don't want to learn yet another huge API in order to bring cross-language capabilities to the applications they develop. J# is a tool to give more power to the applications they develop under the .NET Framework, using more or less the same language.
J# can be seen as the only language under the .NET Framework that directly supports the syntax and API (to a certain extent) of any existing language. This also can be seen as a step toward making JUMP (Java User Migration Path) a reality.
The following section shows many examples of how this tool makes life easier for the Java developer, irrespective of the framework used to develop applications.