docs/tutorial/demo.md

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# Scala and Java Examples

[Scala and Java Examples](https://github.com/apache/sedona/tree/master/examples) contains template projects for Sedona Spark (RDD, SQL and Viz) and Sedona Flink. The template projects have been configured properly.

Note that, although the template projects are written in Scala, the same APIs can be  used in Java as well.

## Folder structure

The folder structure of this repository is as follows.

* spark-sql: a Scala template shows how to use Sedona RDD, DataFrame and SQL API
* flink-sql: a Java template show how to use Sedona SQL via Flink Table APIs

## Compile and package

### Prerequisites

Please make sure you have the following software installed on your local machine:

* For Scala: Scala 2.12
* For Java: JDK 1.8, Apache Maven 3

### Compile

Run a terminal command `mvn clean package` within the folder of each template

### Submit your fat jar to Spark

After running the command mentioned above, you are able to see a fat jar in `./target` folder. Please take it and use `./bin/spark-submit` to submit this jar.

To run the jar in this way, you need to:

* Either change Spark Master Address in template projects or simply delete it. Currently, they are hard coded to `local[*]` which means run locally with all cores.

* Change the dependency packaging scope of Apache Spark from "compile" to "provided". This is a common packaging strategy in Maven and SBT which means do not package Spark into your fat jar. Otherwise, this may lead to a huge jar and version conflicts!

* Make sure the dependency versions in build.sbt are consistent with your Spark version.

## Run template projects locally

We highly suggest you use IDEs to run template projects on your local machine. For Scala, we recommend IntelliJ IDEA with Scala plug-in. For Java, we recommend IntelliJ IDEA and Eclipse. With the help of IDEs, **you don't have to prepare anything** (even don't need to download and set up Spark!). As long as you have Scala and Java, everything works properly!

### Scala

Import the Scala template project as SBT project. Then run the Main file in this project.