docs/quickstart/java_api_quickstart.md

---
title: "Project Template for Java"
nav-title: Project Template for Java
nav-parent_id: start
nav-pos: 0
---
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* This will be replaced by the TOC
{:toc}

Start working on your Flink Java program in a few simple steps.


## Requirements

The only requirements are working __Maven 3.0.4__ (or higher) and __Java 8.x__ installations.

## Create Project

Use one of the following commands to __create a project__:

<ul class="nav nav-tabs" style="border-bottom: none;">
    <li class="active"><a href="#maven-archetype" data-toggle="tab">Use <strong>Maven archetypes</strong></a></li>
    <li><a href="#quickstart-script" data-toggle="tab">Run the <strong>quickstart script</strong></a></li>
</ul>
<div class="tab-content">
    <div class="tab-pane active" id="maven-archetype">
    {% highlight bash %}
    $ mvn archetype:generate                               \
      -DarchetypeGroupId=com.alibaba.blink              \
      -DarchetypeArtifactId=flink-quickstart-java      \{% unless site.is_stable %}
      -DarchetypeCatalog=https://repository.apache.org/content/repositories/snapshots/ \{% endunless %}
      -DarchetypeVersion={{site.version}}
    {% endhighlight %}
        This allows you to <strong>name your newly created project</strong>. It will interactively ask you for the groupId, artifactId, and package name.
    </div>
    <div class="tab-pane" id="quickstart-script">
    {% highlight bash %}
{% if site.is_stable %}
    $ curl https://flink.apache.org/q/quickstart.sh | bash -s {{site.version}}
{% else %}
    $ curl https://flink.apache.org/q/quickstart-SNAPSHOT.sh | bash -s {{site.version}}
{% endif %}
    {% endhighlight %}

    </div>
    {% unless site.is_stable %}
    <p style="border-radius: 5px; padding: 5px" class="bg-danger">
        <b>Note</b>: For Maven 3.0 or higher, it is no longer possible to specify the repository (-DarchetypeCatalog) via the command line. If you wish to use the snapshot repository, you need to add a repository entry to your settings.xml. For details about this change, please refer to <a href="http://maven.apache.org/archetype/maven-archetype-plugin/archetype-repository.html">Maven official document</a>
    </p>
    {% endunless %}
</div>

## Inspect Project

There will be a new directory in your working directory. If you've used
the _curl_ approach, the directory is called `quickstart`. Otherwise,
it has the name of your `artifactId`:

{% highlight bash %}
$ tree quickstart/
quickstart/
├── pom.xml
└── src
    └── main
        ├── java
        │   └── org
        │       └── myorg
        │           └── quickstart
        │               ├── BatchJob.java
        │               └── StreamingJob.java
        └── resources
            └── log4j.properties
{% endhighlight %}

The sample project is a __Maven project__, which contains two classes: _StreamingJob_ and _BatchJob_ are the basic skeleton programs for a *DataStream* and *DataSet* program.
The _main_ method is the entry point of the program, both for in-IDE testing/execution and for proper deployments.

We recommend you __import this project into your IDE__ to develop and
test it. IntelliJ IDEA supports Maven projects out of the box.
If you use Eclipse, the [m2e plugin](http://www.eclipse.org/m2e/)
allows to [import Maven projects](http://books.sonatype.com/m2eclipse-book/reference/creating-sect-importing-projects.html#fig-creating-import).
Some Eclipse bundles include that plugin by default, others require you
to install it manually. 

*A note to Mac OS X users*: The default JVM heapsize for Java may be too
small for Flink. You have to manually increase it.
In Eclipse, choose
`Run Configurations -> Arguments` and write into the `VM Arguments`
box: `-Xmx800m`.
In IntelliJ IDEA recommended way to change JVM options is from the `Help | Edit Custom VM Options` menu. See [this article](https://intellij-support.jetbrains.com/hc/en-us/articles/206544869-Configuring-JVM-options-and-platform-properties) for details. 

## Build Project

If you want to __build/package your project__, go to your project directory and
run the '`mvn clean package`' command.
You will __find a JAR file__ that contains your application, plus connectors and libraries
that you may have added as dependencies to the application: `target/<artifact-id>-<version>.jar`.

__Note:__ If you use a different class than *StreamingJob* as the application's main class / entry point,
we recommend you change the `mainClass` setting in the `pom.xml` file accordingly. That way, the Flink
can run time application from the JAR file without additionally specifying the main class.

## Next Steps

Write your application!

If you are writing a streaming application and you are looking for inspiration what to write,
take a look at the [Stream Application Examples]({{ site.baseurl }}/dev/stream/examples.html).

If you are writing a batch processing application and you are looking for inspiration what to write,
take a look at the [Batch Application Examples]({{ site.baseurl }}/dev/batch/examples.html).

For a complete overview over the APIs, have a look at the
[DataStream API]({{ site.baseurl }}/dev/datastream_api.html) and
[DataSet API]({{ site.baseurl }}/dev/batch/index.html) sections.

[Here]({{ site.baseurl }}/quickstart/setup_quickstart.html) you can find out how to run an application outside the IDE on a local cluster.

If you have any trouble, ask on our
[Mailing List](http://mail-archives.apache.org/mod_mbox/flink-user/).
We are happy to provide help.

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