Java environment variables

JAVA_HOME: C:\Program Files\Java\jdk1.8.0_171
JDK_HOME : %JAVA_HOME%
JRE_HOME : %JAVA_HOME%\jre
CLASSPATH: .;%JAVA_HOME%\lib;%JAVA_HOME%\jre\lib
PATH : your-unique-entries;%JAVA_HOME%\bin
This makes it easier to update jdk, just modify JAVA_HOME.