I am trying to run my plugin as an application and I get the following error:

java.lang.illegalstateexception: workspace is closed.

at org.eclipse.core.resources.ResourcesPlugin.getWorkspace(ResourcesPlugin.java:407)

I call the method ResourcesPlugin.getworkspace() on the line which is pointed out by the exception.

Code

IProgressMonitor progressMonitor = new NullProgressMonitor();
IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();

I am using Eclipse plugin project. How do I resolve this?