Developing Java

When you use the JavaCompute node, you customize it to determine the exact processing that it provides.

Before you begin

Before you start your integration nodes or integration servers, make sure that the CLASSPATH environment variable is not set, as it can break classloader isolation. If this variable is set, it modifies the Java™ classloader, which takes precedence over all other classloaders, and unexpected issues can occur. IBM® MQ can set the CLASSPATH to contain values that might interfere with JARs that you deploy when you run the setmqenv command.

About this task

You can add any valid Java code to a JavaCompute node, making full use of the Java user-defined node API to process an incoming message. You can use the Java editing facilities of the Eclipse platform to develop your Java code. These facilities include:
  • Code completion
  • Integrated Javadoc documentation
  • Automatic compilation

The Java user-defined node API includes some extra methods that simplify tasks that involve message routing and transformation. These tasks include accessing named elements in a message tree, setting their values, and creating elements, without the need to navigate the tree explicitly.

Use the Debug perspective to debug a message flow that contains a JavaCompute node. When control passes to a JavaCompute node during debugging, the perspective opens the Java debugger, and you can step through the Java class code for the node.

Developers can use any of the following programming styles:
  • Java Plugin API
  • Java Architecture for XML Binding (JAXB)
  • Document Object Model (DOM)
This section provides the following information on developing Java: