exception in thread 'main' java.lang.NoCla

Question

The following program is throwing error:

public class HelloWorld {
    public static void main(String args[]) {
        System.out.println("Hello World!"); 
    }
}

CLASSPATH C:\Program Files\Java\jdk1.6.0_18\bin\

Path C:\Program Files\Java\jdk1.6.0_18\bin\

JAVAHOME C:\Program Files\Java\jdk1.6.0_18\bin

Can you please tell me the root cause?

Answer 1

The CLASSPATH variable needs to include the directory where your Java programs .class file is. You can include '.' in CLASSPATH to indicate that the current directory should be included.

set CLASSPATH=%CLASSPATH%;.

Answer 2

If you want to 'compile and execute' any java file that you have created using any IDE(like eclipse), just run the below commands:

Compile: javac Users\dhiraj01\workspace\Practice\src\PracticeLogic\Logics.java

Execute: java -classpath Users\dhiraj01\workspace\Practice\src\ PracticeLogic.Logics

Answer 3

if your Program.java is in "src/mypkg/subpkg/" directory:

go to "src" dir

Then to compile use "javac mypkg/subpkg/Program.java"

To run use "java mypkg.subpkg.Program.class"

Answer 4

Your CLASSPATH needs to know of the location of your HelloWorld class also.

In simple terms you should append dot . (means current directory) in the CLASSPATH if you are running javac and java commands from DOS prompt.

Answer 5

Run it like this:

java -jar HelloWorld.jar

Answer 6

I had the same problem, and stumbled onto a solution with 'Build Main Project F11'. The ide brought up an "option" that I might want to uncheck 'Compile on Save' in the Build > Compiling portion of the Project configuration dialog. Unchecking 'Complile on Save' and then doing the usual (for me) 'Clean and Build' did the trick for me.