Beans Binding: A Java Data-Binding Solution with a Serious Problem

n the past couple of years, data binding has emerged as an important concept for GUI development in Java. Its main objective is to simplify the task of syncing a data object's properties with their visual representations on the screen (text fields, tables, combo boxes, etc). JSR 295 (Beans Binding for Java, or simply Beans Binding) aims to deliver a default data-binding specification for the Java platform. Although JSR 295 is not yet part of the official JDK, you can download the reference implementation (at the time of writing, version 1.2.1). The last version was released in November 2007, with no new updates since. Although this signifies a mature and stable code base, a few issues prevent this library from being a perfect data-binding solution (more on that later).

Following a discussion of the types of properties that make up the building blocks of Beans Binding, this article walks you through binding object properties and collections, converting data between the input type and the destination property, and adding validators. It concludes with an examination of where the Beans Binding reference implementation falls short.