Grasshopper, the freely available Visual MainWin^® for J2EE^™, Developer Edition, is a plug-in to the Visual Studio .NET IDE that enables .NET developers to port existing ASP.NET and server applications to J2EE servers.

Visual MainWin introduces a patent-pending compiler that compiles Microsoft Intermediate Language (MSIL) into standard Java bytecode. The Visual MainWin cross compiler is based on the ECMA 334 and 335 standards and the Java Virtual Machine specification.