Welcome to the Ranch
You really need to find out about code conventions, and spread out your code. You can find out about code conventions
here, though that is an old document, and I prefer the different identation conventions
here. By indenting code, you make it much easier to read, and you also make it easier to find mistakes because of unbalanced {}. As it is, you have several lines squashed into one, which makes your code really difficult to read.
Also you will find you ought to avoid
if (...) return true; else return false;
You ought to avoid numbers in your code. If you need to use 100,
you should give it a name as a constant, like this
public static final int BOILING_WATER = 100; That makes it obvious what the 100 means. I can’t tell what 100 means by reading the code. I can’t tell what values are supposed to be accepted and what rejected.
Why are you making everything static? Is it because you have a book which teaches you to put everything into the main method?