What Java is
Developed by Sun Microsystems, it is a programming language specifically designed for writing programs that can be safely downloaded through the Internet without fear of viruses or other harm to computers or files. Using small Java programs called applets, Web pages can include functions such as animations, calculators, and other fancy tricks. Java is a simple, robust, object-oriented, platform-independent, multi-threaded, dynamic, general-purpose programming environment. It is best used for creating applets and applications for intranets, the Internet, and any other complex, distributed network.
The meaning of Internet
The most important technological innovation of our generation, the Internet is actually a network of networks. Originally designed by the U.S. Department of Defense so that a communication signal could withstand nuclear war and serve military institutions worldwide, the Internet was first known as the ARPANet, the most robust communication technology. It is a system of linked computer networks, international in scope, that facilitates data transfer and communication services, such as remote login, file transfer (FTP), electronic mail (e-mail), newsgroups, and the World Wide Web. The Internet greatly extends the reach of each connected computer network (see: network effect, IP).
When you see "internet" written with a lowercase "i," it usually refers to a group of local area networks (LANs) that have been connected by means of a common communications protocol. Many internets exist besides the Internet, including many TCP/IP-based networks that are not linked to the Internet (the Defense Data Network is a case in point).