To be honest I don't know the details, but I though I remember hearing that it was more a case of doing the same thing as Microsoft, releasing a wholly incompat

To be honest I don't know the details, but I though I remember hearing that it was more a case of doing the same thing as Microsoft, releasing a wholly incompatible product with Java at large, even the standard libraries where rendered incompatible. I don't know but I would imaging that you are completely within your right to make Java source code you write, compatible or incompatible with what you see fit. I am not 100% sure of the case, but it seems like that was what the articles where saying when the Google suit was hot in the news. I will go back and see if I can find info on it. EDIT: http://tirania.org/blog/archive/2010/Aug-13.html http://tirania.org/blog/archive/2010/Aug-13.html This would explain why Google went through the trouble of making the Dalvik virtual machine explicitly incompatible with the existing Java virtual machine instructions. yes it seems that the VM that Google used is as Microsoft's was incompatible with vanilla JVM instructions.