Is Java good to use on a web site?
No, rather, in modern web applications, sites, a Java script is used. It is a popular language that is now used more and more often. There are whole companies of developers like https://otakoyi.software/technologies/java-script that can help you
I’m not a programmer, but as far as I know Java is more suitable for building desktop applications. I’ve recently found incredibly informative article on Java and its stong and weak points here https://diceus.com/10-reasons-why-java-is-dominant/ . Hope it will be useful for you too.
It really depends on what you are trying to accomplish. Java is a little tricky because the end user has to have software downloaded on their machine to view Java. If they do not have the download, they will not be able to view the program. However, most Windows browsers include the required software.