Installing the JDK

Step-by-step guide

Download the jdk from the Oracle site - google search jdk download
Extract the tar file to your home
Move the extracted files which should all be within a folder jdk* to /etc - you can move to another location of your choice but be sure to remember where you put it, let's call this <javaHome> and I have used /etc/jdk1.8.0_51
Set the following environment variables in your .bash_profile - if you don't set these tomcat will not be able to execute JSP files
1. PATH=./:$PATH:$HOME:/<javaHome>/bin
  CLASSPATH=/etc/<javaHome>/jre/lib/rt.jar
  JAVA_HOME=/etc/<javaHome>/
  JDK_HOME=$JAVA_HOME
  JRE_HOME=/etc/<javaHome>/jre/
You should be able to type java -version and javac -version
Navigate back to your home directory, be sure you are logged in as yourself and not root
Create a file called SmipleTestApplication.java
Add the following lines of code to it
1. public class SimpleTestApplication
  {
  static public void main( String[] args )
  {
  System.out.println( "Hello world\n");
  }
  }
Save the file and exit back to the command line
Type the following
1. javac SimpleTestApplication.java
Now to run it type
1. java SimpleTestApplication