What in pan-fried sea snakes is a "proposal computer"?

I get this warning message in my Error Log window:

The 'org.eclipse.mylyn.java.ui.javaAllCompletionPropos alComputer' proposal computer from the 'org.eclipse.mylyn.java.ui' plug-in did not complete normally. The extension took too long to return from the 'computeCompletionProposals()' operation.

Is this a problem/should I fix it? If so, how?

I'd read the API doc and see what that message means.