The IDE offers a variety of options for compiling Java programs. Using the Build menu, you can compile all files in a program or only those files that are new or have changed since the last compile.
For help with compiling a program, see:
Compiling a Java Program
Correcting Errors in Source Code
Stopping a Compile
Specifying a Target Directory for a Class File
Saving Compiler Messages
Disabling Compilation of a Java Source File
Deleting .class Files