IntelliJ IDEA
Java
Code Completion
File f = new File("/home");
f.
File
Code Completion
For followers, one thing that helped me (auto complete only showed cast field instanceof etc.) was that I had opened a maven module that didn't link correctly to its children (it had a commented out submodules section), so IntelliJ just showed the maven java files as basically "text" files with a tiny "j" in their icon in the project pane. Fixing up the root maven pom.xml file to include the children dirs as modules and voila, they are treated as real java files again, woot!