I just realized that my install of SeaMonkey 2.49.1 doesn't have Java as a plugin. I know you have to create a symlink for Java to work in SeaMonkey, but I'm at a loss as to how to do it. Can anybody assist?
What is the exact version of Java that you have installed?
Grrrrrrr. Seamonkey is misbehaving all of a sudden lately, randomizing my e-mail and taking forever to load pages! And after all that bragging I did about how awesome Seamoneky is, too.

I never added anything to Seamonkey, not even an ad blocker. It
was awesome until about a week ago and it's been slowly disintegrating since then - even without any updates to it.
I'm testing Chromium (effortless, fast, trouble-free so far) and if Seamonkey continues to act up I may switch to Geary or Thunderbird for e-mail and Chromium for browsing.
I can't answer the Java question... I haven't added anything that I know of
8u151-b12-0ubuntu0.16.04.2
Which is actually Java Version 1.8.0_151
Where is the website that requires java?