You need to have JDK installed before you setup any IDE for java program development.  You can download the latest version of java by clicking on the following link:

https://www.oracle.com/java/technologies/javase-downloads.html

The following screen would appear:

Clicking on JDK download link you can download java standard edition version 13

But if you want to download any previous version, you can scroll down the above page for that.

Clicking any of JDK download link you can the following page:

Click on the desired download link based on the o/s type of your system.

It will ask you to accept the license agreement with the screen: