Transforming embedded Java code into custom tags

When a new technology is introduced, the migration of existing applications to the new technology must be carefully considered. Automation can make some migrations feasible that otherwise may be too risky or expensive to be worth the advantages of the new technology. In this paper we describe a technique for migrating Web applications using embedded Java code into a custom tag implementation. The technique uses source code transformation techniques to analyze and separate the Java from the Web pages. The code is then automatically transformed to custom Java classes which are invoked from the modified Web pages containing custom tags. The result is a Web application with identical function and appearance, but where the business logic (the Java code) has been separated from the presentation (the Web pages).