Open up LinkedList.java in the Eclipse editor.
Click on the class name in the class declaration, eg.
public class LinkedList {
Right click, and select Refactor->Rename from the context menu.
Rename the class to DoubleLinkedList. Check the box that says Update
references.
It'll rename your class, your constructors, your file, and change the
imports and references to your class in any other java source files in
your workspace.
Renaming packages does the same thing if you select Update references -
you don't have to manually change all references in other code.
You can see what's wrong with your project by showing the Problems view
(Window->Show View->Problems). Errors should show up at the top of the view.