How to tell if JRE or JDK is installed
I have one computer that I intentionally installed JDK on. I have another computer with JRE, for, among other things, testing. However, when I got a java application working on this computer, and then tried it on another, it complained that JDK was required. How can I check if JDK was somehow installed on my system? Note: the computer in question is a Mac.
Answer
You can open up terminal and simply type
java -version // this will check your jre version
javac -version // this will check your java compiler version if you installed
this should show you the version of java installed on the system (assuming that you have set the path of the java in system environment).
And if you haven't, add it via
export JAVA_HOME=/path/to/java/jdk1.x
and if you unsure if you have java at all on your system just use find in terminal
i.e. find / -name "java"