dolphinscheduler/docs/docs/en/guide/task/java.md

Overview

This node is for executing java-type tasks and supports using files and jar packages as program entries.

Create Tasks

• Click on Project Management -> Project Name -> Workflow Definition, click on the “Create workflow” button, go to the DAG edit page:

• Drag the toolbar's Java task node to the palette.

Task Parameters

Parameter	Description
Node Name	The name of the set task. The node name in a workflow definition is unique.
Run Flag	Indicates whether the node is scheduled properly and turns on the kill switch, if not needed.
Description	Describes the functionality of the node.
Task Priority	When the number of worker threads is insufficient, the worker executes tasks according to the priority. When the priority is the same, the worker executes tasks by order.
Worker Group	The group of machines who execute the tasks. If selecting Default, DolphinScheduler will randomly choose a worker machine to execute the task.
Environment Name	Configure the environment in which the task runs.
Number Of Failed Retries	Number of resubmitted tasks that failed. You can choose the number in the drop-down menu or fill it manually.
Failed Retry Interval	the interval between the failure and resubmission of a task. You can choose the number in the drop-down menu or fill it manually.
Delayed Execution Time	the amount of time a task is delayed, in units.
Timeout Alarm	Check timeout warning, timeout failure, when the task exceeds the“Timeout length”, send a warning message and the task execution fails.
Module Path	pick Java 9 + 's modularity feature, put all resources into-module-path, and require that the JDK version in your worker supports modularity.
Main Parameter	Java program main method entry parameter.
Java VM Parameters	JVM startup parameters.
Script	You need to write Java code if you use the Java run type. The public class must exist in the code without writing a package statement.
Resources	External JAR packages or other resource files that are added to the classpath or module path and can be easily retrieved in your JAVA script.
Custom parameter	A user-defined parameter that is part of HTTP and replaces ${ variable } in the script .
Pre Tasks	Selects a pre-task for the current task and sets the pre-task as the upstream of the current task.

Example

Java type tasks have two modes of execution, here is a demonstration of executing tasks in Java mode.

The main configuration parameters are as follows:

• Run Type
• Module Path
• Main Parameters
• Java VM Parameters
• Script

Note

When you run the task in JAVA execution mode, the public class must exist in the code, and you could omit writing a package statement.