The only major browser that still officially supports Java is Internet Explorer, although there are workarounds for some of the other browsers. For example, you can switch to Firefox ESR (Extended Support Release), but even that support is likely to disappear before long. Google Chrome, and other browsers that use the same engine, can only be made to show Java content by installing an extension that runs Internet Explorer in a tab.
Java’s impact on security is diminishing, but it’s still being used on older systems where upgrading to newer O/S versions is not possible. There are still a lot of Windows XP systems out there, and most of them are either running older versions of Internet Explorer or Firefox ESR.
If you’re still using Java, you should install the latest version, Java 8 Update 171 (8u171), as soon as possible. The easiest way to check which version you’re running and install any available updates is to visit Oracle’s ‘Verify Java’ page. You’ll need to do that with a Java-enabled browser. Another option is to visit the third-party Java Tester site. Again, this site won’t work unless Java is enabled.