A friend of mine, prominent in the patterns community, told me when the Design Patterns book came out he believed that book would extend the future of C++ by a decade. He may have been right. (Since then other factors such as Boost have had a big influence as well.)
I am here today to make a prediction myself.
I believe that the GCJ compiler for Java will have a substantial influence on that language's future, maybe extending Java's future by a decade. This compiler will itself boost Java on the server, and in conjunction with Eclipse/SWT revitalize Java as a key language for desktop applications.
Moreover a secondary effect will eventually be to influence Microsoft's dotnet approach.
GCJ is a presage of the end of the virtual machine.