Virus code can be coded using several language. The best being c or vbs. Java is one of the least preferred languages for virus coding. If you know c language you will realize that there is only a few difference in coding between them .so all the c virus can be modified into lava.
I am assuming you know at least lava basics. See this c code
So you see this is actually a c virus that eats your system resource i.e memory but can be used as a lava virus too.This is a very simple virus that causes no havoc. Just check out the virus codes in c section for more example codes. Please remember to change these virus codes in c to lava. these changes can even be done by a beginner who know programming and not necessary c/c++