Use expressions to extend the functionality of a Java transformation. For example, you can invoke an expression in a Java transformation to look up the values of input or output ports or look up the values of Java transformation variables.

To invoke expressions in a Java transformation, you generate the Java code or use Java transformation API methods to invoke the expression. You invoke the expression and use the result of the expression on the appropriate code entry tab. You can generate the Java code that invokes an expression or use API methods to write the Java code that invokes the expression.

The following table describes the methods that you can use to create and invoke expressions in a Java transformation: