Sun Microsystems Inc. will release in the near future tools that will finally let Java developers easily link their programs with back-end data and applications.
The tools, Java Blend 2.0 and Java Message Queue (JMQ) 1.0, create a ready-to-use framework for building such links, thus freeing programmers from writing and maintaining this code themselves. In theory, the tools should speed deployment of new Java applications that can work with existing databases and a range of enterprise applications.
Today, creating these links is hard work. Developers have to write their own database access codes using the Java Database Connectivity (JDBC) interface. To let applications share information directly, via reliable message queues, is even harder because until recently there was no Java messaging standard, let alone tools based on a standard.
The Database Link
Java Blend 2.0 is used by a database analyst to translate the internal layout, or schema, of a database into a set of reusable Java objects, such as “customer” and “order.” Or Java Blend can take a set of such Java objects, created by a Java developer, and translate them into a set of database tables for storing data about the customer and order.
Java developers no longer have to understand the inner workings of the database or puzzle over how to create a high-performance query. All that complexity is in the objects, which developers simply incorporate into the finished applications, using a Java development tool.
This will be much simpler than writing low-level JDBC code, according to users such as Rick Bullotta, chief technology officer at Lighthammer Software Development in Malvern, Pa. JDBC is a simple, database-independent API for accessing relational data stores. Java Blend, which essentially automates the creation of JDBC code, is much more flexible and powerful in building data-intensive Web applications, Bullotta said.
Sun has labelled this Release 2.0, but the previous version was only available as an experimental product for developers. In response to user feedback, Sun invested a lot of effort into strengthening the reliability of internal mechanisms, such as memory management, and ensuring that Java Blend could handle hundreds of database connections at the same time, according to Dan Gilliland, a senior product manager.
Java Blend 2.0 has interfaces to Oracle, Sybase and Microsoft databases. The tool, which runs initially on Solaris and Windows NT, costs US$1,195 per developer and will ship later in November.
The Messaging Link
JMQ 1.0 lets Java applications exchange information through a message queue, which can be thought of as a kind of answering machine for applications.
In a message queue environment, applications drop off, or publish, specific information, such as the data in a new customer order. Other applications, such as inventory or credit authorization, pick up, or subscribe to, the data they need to know.
With this publish/subscribe approach, users can add or drop applications without forcing developers to make changes elsewhere in the net, said Dennis Yocum, Sun’s senior product manager for JMQ.
JMQ is based on the Java Message Service, a recent addition to the Java2 Enterprise Edition specification. Other companies are building similar application messaging products, and Progress Software has already released one called SonicMQ.
There are two parts to JMQ, which is based on middleware that Sun licensed earlier this year from Enron Communications. A server program called the router moves messages between queues. The Java developer then incorporates into the application a set of JMQ client libraries, which contain ready-to-use code for handling communications with the router.
The developers’ version of JMQ will be available later this year, priced at $495 per developer. It runs initially on Solaris and Windows NT. The final production version will be ready during the first quarter of 2000.