Reuse of existing libraries simplifies software development efforts. However, these libraries are often complex and reusing the APIs in the libraries involves a steep learning curve. A programmer often uses a search engine such as Google to discover code snippets involving library usage to perform a common task. A problem with search engines is that they return many pages that a programmer has to manually mine to discover the desired code. Recent research efforts have tried to address this problem by automating the generation of code snippets from user queries. However, these queries need to have type information and therefore require the user to have a partial knowledge of the APIs. We propose a novel code search technique, called SNIFF, which retains the flexibility of performing code search in plain English, while obtaining a small set of relevant code snippets to perform the desired task. Our technique is based on the observation that the library methods that a user code calls ...