The Java Decompiler is a work in progress.

Imports is partially done now. Currently, I'm picking up all the class names from the fields, and adding the classes to the imports section. In addition, generics in field names are now supported as well.

The generic names were picked up from the Signature attribute, which appears in the Attributes section of ClassFile, Method_Info, Field_Info structures of the class file. See JVM Specification, 4.7.