Some points to answer this question: In C++ it is the developer who has to take care of freeing memory space for objects that are no longer being referenced. In JVM it will be a garbage collector equivalent that will be doing this job for you. So one of the challenges would to to take care of that portion of the C++ compiled code so that we can let JVM handle it. Another challenge would the the use of pointers in C++, due to which it is possible to access memory of other objects leading to errors. This is another challenge that will need to be tackled as the JVM (depending on language specific implementation), may not be using pointers and also may not allow accessing memory of other objects. You will need to be aware of the language specific implementation changes that JVM has with C++ compiled code and these will need to be tackled (these sections of code need to be changed so that the compiled code can no be seamlessly converted to a JVM byte code.