The S/Java interface is a programming environment that links the S and Java languages. In this environment programmers can quickly, and with little programming effort, link the data organizing and analysis capabilities of S with methods and toolkits for user interaction and graphics found in Java.

The S language is the standard medium for implementing new techniques arising from Bell Labs research in statistics, and for transferring the techniques to our Lucent Technologies colleagues; in addition, many of our collaborators themselves implement and adapt software in S for their own needs.

The interface exploits the object-oriented features of both S and Java. Programmers typically begin with existing software in Java for interactive graphics and existing S software for computing with data. Linking the software amounts to designing the information content the two sides want to share. Specifically, the programmer designs a class (often a simple one) to represent the data. We provide tools to handle the class in both S and Java, and to communicate objects in either direction.

This approach produces a universal interface in several senses:

The data transmission uses a standard, open format for S objects, defined in Version 4 of S . Our interface includes methods to transmit objects in either direction, given the definition of the class, so data transmission is transparent to the programmer, regardless of the class being used.

Actual data transmission is handled by a Java object server . Although the data format is completely general, it is simple enough that other versions of S or even other systems can send or receive objects through the server. We anticipate that the S/Java interface can grow in this way to a co-ordinated interface among many systems.

The use of Java to read and evaluate the objects means that the interface is geographically universal as well: the object server (e.g., S) and the applet viewer can communicate from any locations on the net.

Java is rich enough and has enough in common with S to make the graphics and interaction possibilities unlimited as well. All standard S graphics can be produced, but can also be extended in many ways (e.g., animation). Specialized displays and interactions can be programmed directly in Java, using the S object as the source of data for the display.

The interface can be used either on-line through a Java applet that supports running S, or off-line through URL's generated from the interface. The online interface lets S programmers develop new techniques for use with Java, using all the features of S. The off-line interface captures the output of the techniques and makes them immediately usable in Java applets unconnected with S. In particular, results can be developed in a secure environment and then inserted into an applet on a generally accessible site, with interaction and graphics using the Java methods, but without compromising the security of the underlying data.