How do i know if my imac has java

Go to Java website

https://www.java.com/en/download/faq/java_mac.xml

and then this section.

» How do I know if I have Java installed on my Mac?

Are you getting a message window indicating that some app requires Java? If you are I would suggest you install the Apple legacy Java 6, Java for OS X 2014-001 , before trying Oracle's version. The Adobe apps require the Apple legacy version and won't run on the Oracle version. Also read this: Installing Java on a Mac? Beware the now-bundled Ask.com toolbar. It's referring the Oracle offering of Java.