---
category: academic
type: academic
person: Yanxin Lu
date: 2005
source: balaban_05_migration.pdf
---

# Refactoring Support for Class Library Migration

Ittai Balaban (NYU), Frank Tip, Robert Fuhrer (IBM T.J. Watson Research Center)

OOPSLA 2005

As object-oriented class libraries evolve, classes are occasionally deprecated in favor of others with roughly the same functionality. In Java, for example, Hashtable has been superseded by HashMap, and Iterator is now preferred over Enumeration. Migrating client applications to use the new idioms is desirable, but making the required changes to declarations and allocation sites can be quite labor-intensive. Moreover, migration becomes complicated if a legacy class is not completely equivalent to its replacement, or if multiple interdependent classes must be migrated simultaneously.

The authors present an approach in which mappings between legacy classes and their replacements are specified by the programmer. Then, an analysis based on type constraints determines where declarations and allocation sites can be updated. The method was implemented in Eclipse, and evaluated on a number of Java applications. On average, the tool could migrate more than 90% of the references to legacy classes.