Add existing file (to project) in Eclipse

1.Copy the preexisting source files you which add to your project.
2.In Project Explorer, right click your project and select New > File
3.In the “New File” dialog box, your project’s name / folder should be displayed as the parent folder for your new (existing) source file.
4.Click on the “Advanced” button at the bottom of the “New File” dialog box.
5.Check the “Link to file in the file system” checkbox.
6.Click the “Browse” and browse to your preexisting source.
7.Click the “Finish” button at the bottom of the dialog box.