The essentials of modern software development (such as low cost and high efficiency) demand software developers to make intensive reuse of existing open source frameworks or libraries (generally referred as frameworks) available on the web. However, developers often face challenges in reusing these frameworks due to several factors such as the complexity and lack of proper documentation. In this paper, we propose a code-search-engine-based approach that tries to detect hotspots in a given framework by mining code examples gathered from open source repositories available on the web; these hotspots are the APIs that are frequently reused. Hotspots can serve as starting points for developers in understanding and reusing the given framework. We developed a tool, called SpotWeb, for frameworks or libraries written in Java and conducted two case studies with two open source frameworks JUnit and Log4j. We also show that the detected hotspots of Log4j and JUnit are consistent with their respective documentations.