You can compile once and the program will run on a Mac, PC, etc. Java supports drop-in components, called Java Beans. You can drop in a button, a spread sheet, or whatever you like. Java is secure. You can download stuff to your machine but it can't get to anything on your machine.
Network programming is very fast.
You can give users the chance to change the look and feel of a page. JDBC is between you and the database. Java started in 1996. Java is international. It uses a 2-byte code.