How to check if Java is working, do you have three of them installed?

Question

Java

Three versions of java are installed: 6, 7, 8
Paths are set via JAVA_HOME / PATH variables
JAVA_HOME, JAVA_6_HOME, JAVA_7_HOME, JAVA_8_HOME,
I can only check the state of JAVA_HOME, How can I check the rest?
The program reads all three java.
OS: Centos in aws

Answer 1

path/to/jre/bin/java -version
For each JRE version