2.6. JDK Requirements

Your system must have the correct JDK installed on all the nodes of the cluster. HDP requires Oracle JDK 1.6 update 31.

Use the following instructions to manually install JDK 1.6 update 31:

Check the version. From a terminal window, type:
```
java -version
```
(Optional) Uninstall the Java package if the JDK version is less than v1.6 update 31.
```
rpm -qa | grep java
yum remove {java-1.*}
```
(Optional) Verify that the default Java package is uninstalled.
```
which java
```
Download the Oracle 64-bit JDK (jdk-6u31-linux-x64.bin) from the Oracle download site:
```
http://www.oracle.com/technetwork/java/javasebusiness/downloads/java-archive-downloads-javase6-419409.html#jdk-6u31-oth-JPR
```
Accept the license agreement.

Change directory to the location where you downloaded the JDK and run the install.

mkdir /usr/jdk1.6.0_31
cd /usr/jdk1.6.0_31
chmod u+x $JDK_download_directory/jdk-6u31-linux-x64.bin
$JDK_download_directory/jdk-6u31-linux-x64.bin

Create symbolic links (symlinks) to the JDK.

mkdir /usr/java
ln -s /usr/jdk1.6.0_31/jdk1.6.0_31 /usr/java/default
ln -s /usr/java/default/bin/java /usr/bin/java