Compile the File

To compile the file, do this:

The command javac Hello.java runs the Java compiler on the source file. Be sure to get upper and lower case correct on the file name.

If you do not have the Java Development Kit (JDK) installed on your computer, this will not work. Install the Java Development Kit (JDK) from Oracle.

If you install BlueJ, it will also install the JDK and you will be able to run Java from the command prompt. To install BlueJ, go here: BlueJ.

Type DIR again to see the result of compiling Now there are two files in the directory: the source file and the file of bytecodes Hello.class that the compiler produced. The DIR shows that the bytecode file contains 116 bytes.