# User Defined tab

![User Defined tab, Pentaho MapReduce](/files/FtzvUgTzKLSHhF6IemFl)

The following table describes the options for defining user-defined parameters and variables:

| Column    | Definition                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| --------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Name**  | Enter the name of the user-defined parameter or variable that you want to set. To set a java system variable, preface the variable name with `java.system` (**java.system.SAMPLE\_VARIABLE** for example).Kettle variables that are set here override the Kettle variables set in the `kettle.properties` file. For more information on how to set a kettle variable, see [Kettle Variables](/pdia-data-integration/10.2-data-integration/data-integration-perspective-in-the-pdi-client/advanced-topics-pdi-perspective/pdi-run-modifiers/variables/kettle-variables.md). |
| **Value** | Enter the value of the user-defined parameter or variable that you want to set.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |


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