Running java helloworld

Question

I tried to google this, went to oracle.com and read all the questions on this forum related to this. I wrote a simple "Helloworld" program

package helloworld;

public class Helloworld {
    public static void main(String[] args) {

        System.out.println("Hello World!");
    }
}

NetBeans compiles the source code into a .class file. I move that file to C:\MyJava

I try to run it by C:\MyJava> java -cp . Helloworld and all possible variations of such. I keep getting the NoClassDefFoundError: Helloworld (wrong name: helloworld/Helloworld).

To make sure. There's a question almost exactly like this (difference in "wrong name"). The solution to that question does not work in my case.

package hello world is an invalid package declaration, I assume you want package hello.world; instead. — Thomas
– Thomas, Commented Jul 24, 2012 at 8:50
C:\MyJava>cd helloworld then C:\MyJava\helloworld>java Helloworld .run it like this it will work where helloworld is your packagename.Copy the .class with package(folder). — Dangling Piyush
– Dangling Piyush, Commented Jul 24, 2012 at 8:51

Jesper · Accepted Answer · 2012-07-24 08:51:39Z

8

You get the "wrong name" error because your class is in the package helloworld. Java expects you to provide the fully-qualified class name on the command line:

C:\MyJava> java -cp . helloworld.Helloworld

The directory structure must match the package structure. This means that you should have a directory C:\MyJava\helloworld that contains the class file Helloworld.class.

answered Jul 24, 2012 at 8:51

Jesper

208k47 gold badges325 silver badges361 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

PBD10017 Over a year ago

Jesper, thanks so much. I don't know if this was supposed to be obvious, but it sure wasn't to me. Thank you.

Jon Lin · Accepted Answer · 2012-07-24 08:50:36Z

6

You need to tell it the package name (which is helloworld):

C:\MyJava> java -cp . helloworld.Helloworld

answered Jul 24, 2012 at 8:50

Jon Lin

144k29 gold badges226 silver badges224 bronze badges

2 Comments

PBD10017 Over a year ago

Thanks Jon Lin. Your answer is right as well. Jesper added the package/folder structure that needs to be present to run java. Thanks.

zip Over a year ago

you do not need to specify a classpath pointing to ".". This is default behaviour ;)

Community · Accepted Answer · 2017-05-23 12:17:33Z

0

Below post is similar to your problem. I hope it guides you;

How do I run .class files on windows from command line?

edited May 23, 2017 at 12:17

CommunityBot

11 silver badge

answered Jul 24, 2012 at 8:52

Ufuk Şengül

111 bronze badge

1 Comment

Undisputed007 Over a year ago

This is not an answer. Use comments..oh you dont have enough rep for comments

Collectives™ on Stack Overflow

Running java helloworld

3 Answers 3

1 Comment

2 Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

2 Comments

1 Comment

Linked

Related