<p>I am using Eclipse for quite some time and I still haven't found how to configure the Problems View to display only the Errors and Warnings of interest. Is there an easy way to filter out warnings from a specific resource or from a specific path? For example, when I generate javadoc I get tons of irrelevant html warnings. Also, is there a way to change the maximum number of appearing warnings/errors?</p>

<p>I am aware of the filters concept, but I am looking for some real life examples. What kind of filters or practices do other people use?</p>

<p><strong>Edit:</strong> I found the advice to filter on "On selected element and its children" to be the best one. I have one other issue however. If I have "a lot" of warnings or errors, only the first 100 appear. In the rare case I want to see all of them, how do I do it?</p>

In the top right hand corner of the problems pane is a filter button (it looks like three arrows pointing to the right), clicking that will let you configure the view.  You can filter by element, such as the class you're editing or working set, the type of problem (e.g. java problems, buildfile problems etc..) and by severity.  It's actually very configurable.
See
http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.platform.doc.user/concepts/cprbview.htm
for details and screenshots.