Allows the Pipeline script to pass structured objects to the external Groovy script and receive structured return values. The values must be Serializable and may only refer to types defined in the Java Platform or Groovy language. If set to any non-null value, the external script may call the following methods:

Pipeline.input()

Returns the object passed in this parameter.

Pipeline.output(object)

Saves an object to be used as the return value of this step.

(If your script passes -cp / -classpath, be sure to append/prepend $CLASSPATH / %CLASSPATH%.)