Hadoop is written in Java, so you will need a recent Java Development Kit (JDK) installed br on the Ubuntu host. Perform the following steps to check the prerequisites: br br 1. First, check what's already available by opening up a terminal and typing br the following: br $ javac br $ java -version br br 2. If either of these commands gives a no such file or directory or similar br error, or if the latter mentions "Open JDK", it's likely you need to download the full br JDK. Grab this from the Oracle download page at br technetworkjavajavasedownloadsindex.html; you should get the br latest release. br br 3.