* Java This is an outline on how to support Java, actual implementations of ideas like this can be found here It would be interesting to support the Java language as part of the Mono project. You have to think of Java as various pieces: Java the language and Java the virtual machine. It is possible to compile Java to .NET, as shown by the Microsoft J# compiler. We could then allow the migration of Java applications to the Mono runtime. ** Native compiler Although a native compiler can be built, and probably should be built using an existing compiler, a short term solution is to build a translator from Java class files to the ECMA CIL images. This has the advantage that we can use an existing and tested Java compiler to generate the code, and then we can use an automated code compiler that compiles Java VM bytecodes to CIL bytecodes. ** The translator. It would be interesting to write a semantic translator that converts java byte codes into CIL opcodes. This is possible because the Java byte codes are a subset of the CIL ones. A semantic tree needs to be constructed (very much in the spirit of what is done in mono_analize_stack in mono/mono/jit/jit.c. Once such a semantic tree is constructed, we could generate the equivalent Java code. This has a number of interesting side effects: people can continue to use their existing Java compilers to compile their code, and a simple tool that converts their .class files into a .NET assembly can be used. ** Libraries We could translate the GNU Classpath libraries with the above tools to provide the Java runtime required to host into the Mono runtime. Some special treatment would be required for core data types like integers, arrays and strings, and of course reuse where possible existing classes from .NET to make them compatible. ** JILC - Java to IL Compiler This is an attempt to make the java bytecode available for the .NET environment. The project attempts to generate the IL code / bytecode from the compiled java class files. It has reached the stage of code-generation. The issues that needs to be addressed is the mapping of java objects to the IL objects, eg: java.lang.String to System.String. Gaurav Vaish and Abhaya Agarwal are currently leading this project. The project is currently hosted at SourceForge.Net. The official home page of the project is http://jilc.sourceforge.net.