I found one great thing Eclipse can do for us. That is to merge multiple projects to one.
If I have multiple child projects, please see the direcotry structure.
MyWorkspace
-----MyProject
----------ChildProject1
---------------.classpath
---------------.project
----------ChildProject2
---------------.classpath
---------------.project
Please notice that there is no project file and classpath file in project MyProject . Now I new a project in Ecipse and specify the anme MyProject . Then the project is created, it will merge the two classpaths file from ChildProject1 and ChildProject2. Then you find the directory structure is like,
MyWorkspace
-----MyProject
----------.classpath
----------.project
----------ChildProject1
---------------.classpath
---------------.project
----------ChildProject2
---------------.classpath
---------------.project
What I think is great thing is Eclipse merge the 2 projects and create a whole project. I is a great behavior.