If you receive this error, UNIX cannot find the compiler, javac.
javac: Command not found - after installing Java
Here's one way to tell UNIX where to find javac. Suppose you installed the JDK in /usr/local/jdk1.8.0. At the prompt you would type the following command and press Return:
Note: If you choose this option, each time you compile or run a program, you'll have to precede your javac and java commands with /usr/local/jdk1.8.0/. To avoid this extra typing, you could add this information to your PATH variable. The steps for doing so will vary depending on which shell you are currently running.
Class names, 'hello', are only accepted if annotation processing is explicitly requested
If you receive this error, you forgot to include the .java suffix when compiling the program. Remember, the command is javac hello.java not javac hello.
For more details, consult this lecture "Creating a Hello World application" in this page. http://learnjavaeasy.com/course/lear...8-by-examples/