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# Prerequisites

You require a JDK 8 in order to run openHAB. Note that there are often issues with OpenJDK, therefore it is advised to use the OracleJDK instead.

Check that the correct version of Java has been installed:

* Open the terminal window

* Type the following command `java -version`

* You should see something like this :

```
cal:~ callas$ java -version
java version "1.8.0 73"
Java(TM) SE Runtime Environment (build 1.8.0_73-b02)
Java HotSpot(TM) 64-Bit Server VM (build 25.73-b02, mixed mode)
```

