The Java transformation initializes the value of unconnected input ports or output ports that do not have an assigned value in the Java code snippets.
Java transformation initializes ports based on the following Java data types:
Primitive data type
If you define a default value for the port that is not equal to null, the transformation initializes the value of the port variable to the default value. Otherwise, it initializes the value of the port variable to 0.
Complex data type
If you define a default value for the port, the transformation creates a new object, and initializes the object to the default value. Otherwise, the transformation initializes the port variable to null. For example, if you define a default value for a string port, the transformation creates a new String object, and initializes the String object to the default value.
If you access an input port variable with a null value in the Java code, a NullPointerException occurs.
You can enable an input port as a partition key and a sort key, and you can assign a sort direction. The Data Integration Service partitions the data and sorts the data in each partition by the sort key and sort direction. The Partition Key and Sort Key are valid when the transformation scope is set to All Input.
Use the following properties for partitioning and sorting data:
Partition Key
Input port that determines the rows of data to group into the same partition.
You can enable one or more input rows as partition keys. The Data Integration Service uses the partition keys to repartition the data before the code runs. If you do not select an input row as a partition key, the data is processed using its default partitioning scheme.
Sort Key
Input port that determines the sort criteria within each partition.
Direction
Ascending or descending order. Default is ascending.