Step:1 go to this link, https://www.oracle.com/technetwork/java/javase/downloads/index.html at the top of the page you will see a title “Java SE Downloads”.
Note: Java has different Programming Language platforms,
1. Java SE(Standard Edition) – for normal use (it is the core platform of all other Editions).
2. Java EE(Enterprise Edition) – for large scale development (like servers).
3. Java ME(Micro Edition)-for small scale development (mobile phones).
4. JAVA FX – for making internet application with great User Interfaces.
Step:2 click Java Platform(JDK), at the bottom of the page you will see a table with all the Java SE JDK packages for different OS’s.
Step:3 download the suitable package for your OS(download .exe file for windows).
Note: some java JDK versions are not available for 32 bit OS. If it is, then go back and try to use a different version in the Java SE platform table.
JDK ver 8 supports for both 64 and 32 bit os, so try that one.
Step:4 once the package is downloaded in the machine just open it.,
a setup wizard will be opened with a “Next” button(Now I am installing JDK ver 12.0.1), just click the Next button and install the package (what I recommend you just keep all the things as default–> do not try to change the location that the files are going to be installed).
After the installation process is done. just “Close” it.
But still, you are not able to develop Java programs on your machine. you will have to do last few steps– you have to create an Envioranmt variable for your JDK.
Step:5 go to your JDK installed location, if you keep the location as default then the JDK will be installed in your “program files” in C: drive (you will see a folder called “Java” in your program files, just open that).just go to “bin” folder, and copy the path to that folder.
Note: bin folder contains all the library files that are needed to run and develop java programs.
Step:6 Right-click “This PC” and go to properties, in the left of the opened window, you will see an option “Advanced system settings”, Just click that option.
Another window called “System Properties” will be opened. In that window just go to the “Advanced” menu at the top. Inside this “Advanced” menu, you will see a button “Environment Variables..”, just click that.
Once you clicked it, another window will be opened, just double click the variable called “Path” at the top.
In the newly opened window, click the “New” button in order to add the path of your bin folder in JDK( just paste the path that you copied before ), click “Ok”
Good: you are done.
To check whether the JDK works well or not, go to Command Prompt(CMD) and type “javac”. if you get a big list of words, then it works properly. if it is not, watch the video below and see what steps you missed.
click here:- How to install JDK(Java Development Kit) on Ubuntu OS
logic behind the code 