1.Downloading the installer：http://www.oracle.com/technetwork/java/javase/downloads/index.html
2.Running the JDK installer：
3.Updating the environment variable：
1)Click start, then control panel, then system.
2)Then advanced, then environment variables.
3) Add the location of the bin folder of the JDK installation to the path variable in system variables, the following is a typical value for the path variable:
C:\WINDPWS\system32;C:\WINDPWS;C:\Program Files\Java\jdk1.8.0\bin
Note:
1)The PATH environment variable is a series of directories separated by semicolons (;) and is not case-sensitive. Microsoft Windows looks for programs in the PATH directories in order from left to right.
2)You should only have one bin directory for a JDK in the path at a time. Those following the first instance are ignored.
3)If you are not sure where to add the JDK path, append it.
4)The new path takes effect in each new command window you open after setting the PATH variable.
4.Starting to use the JDK：
If you are new to develping and running programs in the java programming language, you can download the documentation from http://www.oracle.com/technetwork/java/javase/downloads/index-jsp-138363.html page for some guidance.
5.Uninstalling the JDK
To uninstall the JDK, use the "Add/Remove Programs" utility in the Microsoft Windows Control Panel.