What is a Workspace

When you start Eclipse you are asked to indicate a workspace directory.

The workspace is a directory on the disk where the Eclipse platform and all the installed plug-ins store preferences, configurations and temporary information. Subsequent Eclipse invocations will use this storage to restore the previous state.
As the name suggests, it is your “space of work”. It defines your area of interest during an Eclipse session.
In a workspace you define projects that reference your disk resources. You don’t have to move source files into the workspace. And projects don’t import or copy source files into the workspace. Instead projects point to any folder or files on your disk.

Warning

We don’t recommend keeping source code files in the workspace.

Each time you start Eclipse you can create a new workspace directory or indicate an existing one. You can create many workspaces, each one dedicated to some activity. You may use one workspace for developing your current project and another for maintaining the previous one. If the two activities are unrelated, in doing so you minimize clutter and improve performance by using two workspaces.

You can launch several Eclipse applications in parallel, but one workspace can be used only by one Eclipse instance that locks it :

./workspace-dir/
├── .metadata/
│   ├── .lock
└── ...

Warning

If you try to use an workspace already in use by an existing Eclipse instance, you’ll be signaled “Workspace in use or cannot be created, choose a different one”.

You can switch at anytime to another workspace from menu File ‣ Switch Workspace…, but launching different Eclipse for different workspaces is common practice.