You must compile the classes in Fig. B.1 and Fig. B.2 before you can execute the application. First, change to the directory that contains the application’s source-code files. Next, type the command
javac GradeBook.java GradeBookTest.java
to compile both classes at once. If the directory containing the application includes only this application’s files, you can compile all the classes in the directory with the command
javac *.java
The asterisk (*
) in *.java
indicates that all files in the current directory that end with the file-name extension “.java
” should be compiled.