Step 3: Run the Java Program
Now that the program is compiled, we can run it!
- In CMD, type:
java MyFirstProgram
2. Press Enter.
If everything is correct, you will see this output:
Hello, Java!
Click here for an explanation on java and javac commands
The javac command is used to compile your Java source file (.java) into a bytecode file (.class). For example, if your file is named MyFirstProgram.java, you would use the command javac MyFirstProgram.java to compile it. If there are any errors in your code, the compiler will display them, and no bytecode will be created. Once the code is error-free, the java command is used to run the compiled program. For example, you would type java MyFirstProgram to execute the program, without adding .class at the end. This will start the program and display the output on your screen.
Summary:
🔹 Create a Folder for Your Project
(e.g., JavaProjects → FirstProgram)
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🔹 Open Notepad and Write Code
(Save as MyFirstProgram.java in FirstProgram folder)
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🔹 Open CMD in the Folder
(Go to FirstProgram folder, click in the address bar, type 'cmd' and press Enter)
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🔹 Compile the Java Program
Command: javac MyFirstProgram.java
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🔹 If No Errors, Bytecode is Created (MyFirstProgram.class)
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🔹 Run the Program
Command: java MyFirstProgram
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✅ Output Appears on Screen: "Hello, Java!"