What Is The Difference between JDK and JRE
JRE is Java Runtime Environment simply is the Java virtual machine (JVM) which provides you the Environment to run Java programs and applications.
JDK - is Java Development Kit is a development package for programmers which Also include the JRE.
If you Installed JDK, you don't want to install JRE, because jre includes in JDK package.
What Should I Install JRE or JDK
If you Only want to run applications or software base on Java just install JRE. And If you're a Java programmer then you need to install the JDK , Which provides the Java compiler (javac) and Software development kit.