When you install a Java update, they use the defaults as an opportunity to change your default search engine and stick an unwanted toolbar onto your browser. Why do they recommend it? Because they get paid.
If you don’t think that changing your search engine is worth much, think about Google. In 2011, Google earned $26 Billion dollars from their web sites, most of that was from ad revenue related to search.
Why does Norton security try to get you to install their toolbar on exit? Don’t be fooled by the scary language. They want you to use their search engine so they can make more money.