java command-line tool

Running OS 10.12.3, and possibly while running Safari, I keep getting a window:
"To use the "java" command-line tool you need to install a JDK."
Why do I need it? What does it provide? Should it be ignored or how do I prevent it appearing?
Hamish

Java is a programming language. JDK is "Java Development Kit" and is how Java runs.

You are being told that to do what you want to do in Safari requires Java. Probably because what you want is written in Java. However, Java is full of security holes and not really safe to use in the Internet environment, IMHO. So I would answer "Ignore it." Depending on what you want to do, you may not be able to prevent the message.

If you tel us what you were trying to do, we can give better advice, but in general, you should not need Java. I don't have it installed and don't see any need to do so.

Hi,

I am having the same issue as Hamish. Running the same system. The window won't go away. Do I just go to library/application support/java and delete java?

No, the problem is you DON'T have Java and you are trying to execute something written in Java. If you must have that application/script/website run, you will need to install Java. But as I said, I personally don't recommend you do that. Just stop going to where you are being told you need Java.