public class FirstSample
{
public static void main(String[] args)
{
System.out.println("We will not use 'Hello, World!'");
}
}
It is worth spending all the time that you need to become comfortable with the framework of this sample; the pieces will recur in all applications. First and foremost, Java is case sensitive. If you made any mistakes in capitalization (such as typing Main instead of main), the program will not run.
The standard naming convention (which we follow in the name FirstSample) is that class names are nouns that start with an uppercase letter. If a name consists of multiple words, use an initial uppercase letter in each of the words. (This use of uppercase letters in the middle of a word is sometimes called "camel case" or, self-referentially, "CamelCase.")
You need to make the file name for the source code the same as the name of the public class, with the extension .java appended. Thus, you must store this code in a file called FirstSample.java. (Again, case is important—don't use firstsample.java.)
If you have named the file correctly and not made any typos in the source code, then when you compile this source code, you end up with a file containing the bytecodes for this class. The Java compiler automatically names the bytecode file FirstSample.class and stores it in the same directory as the source file. Finally, launch the program by issuing the command:
java FirstSample
(Remember to leave off the .class extension.) When the program executes, it simply displays the string We will not use 'Hello, World'! on the console.
Notice the braces { } in the source code. In Java, as in C/C++, braces
delineate the parts (usually called blocks) in
your program. In Java, the code for any method must be started by an opening
brace { and ended by a closing brace }.
