How to Run Java Applications using the Windows Command Prompt.

Julian FalascaMay 11th, 2010

ENGL 393

Introduction

• Purpose: Most IS courses don’t touch this topic.

• Target Audience: Students already familiar with Java programming. (CMSC and IS majors)

• When to Use: On the job.• Safety Information: Don’t get too excited.

Materials Needed

• At least 1 valid java source file. (HelloWorld.java)– Must know where this file is located.

• Java Development Kit (JDK) already installed.– http://java.sun.com/javase/downloads/index.jsp

Step 1• Click on Start, Programs, Accessories, and

select Command Prompt.

Example Command Prompt

Step 2

• This example uses a java file which is located:D:\Workspace\HelloWorld.java

• Type d: and press enter.– This command changes directories to the D drive.

Example Command Prompt

Step 3

• Type cd Workspace and press enter.– This takes you into the Workspace directory.

Example Command Prompt

Step 4

• Type dir and press enter.• This displays a list of files in the current directory.– Confirm that HelloWorld.java is in the list.

Example Command Prompt

Step 5

• Type javac HelloWorld.java and press enter.– This compiles the file, allowing you to run it.• A new file has been created named HelloWorld.class.

Example Command Prompt

Step 6

• Type java HelloWorld and press enter.– The Java application will run.

Example Command Prompt

Conclusion

• Warranty Information: N/A• Technical Support: Lookup commands on google.• FAQs: – Why do I get the error “javac command not

recognized”?• Most likely you have not installed the JDK correctly.

– How do I go to the previous directory?• Type cd .. and press enter.

Conclusion ContinuedProblem Cause Solution

When compiling you get the following error: Class names, ‘HelloWorld’, are

only accepted if annotation processing is explicitly

requested.

You typed javac HelloWorld You must include the file extension when compiling. Type javac HelloWorld.java

When running the application you get the

following error: Exception in thread “main”

java.lang.NoClassDefFoundError: HellowWorld/class

You typed java HelloWorld.class

You cannot include the extension when running.

Type java HelloWorld

Questions?