The difference between JDK and JRE

The first is that the target groups are different

JDK is an SDK for developers 

JRE is the Java Runtime Environment. It is the running environment of the java program. It is for the users of the java program. Of course, when the java programmer develops, the JRE is also needed, the program needs to be debugged, and the code runs.

• If you install jdk, there will be two sets of jre
• If jre is installed, there is a unique set of jre