Java - Hello World Error

Question

I'm currently learning Java. My background is primarily in C#. I'm trying to do a basic "hello world". Currently, i've written the following code in IntelliJ:

import java.io.Console;

public class HelloWorld {

    public static void main(String[] args) {
        System.out.println("hello world.");
    }
}

My app compiles successfully. However, when I attempt to run it, I get a runtime error that says:

Exception in thread "main" java.lang.ClassNotFoundException: com.company.Main
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:190)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:113)

Process finished with exit code 1

I don't understand what's happening. Can someone please help me?

How are you trying to run this code? Also I don't see any package in your code while error says that you are trying to run Main class from com.company package. — Pshemo
– Pshemo, Commented Mar 5, 2014 at 15:21
you do not need to call main directly. your class name is HelloWorld. JVM calls main method inside it. so just run as "java HelloWorld" — Sagar Gandhi
– Sagar Gandhi, Commented Mar 5, 2014 at 15:22

slartidan · Accepted Answer · 2014-03-05 15:26:36Z

4

It seems like you told IntelliJ to call the main method of class com.company.Main. But IntelliJ cannot find such a class. IntelliJ searches for a file Main.class in a folder com/company

Probably you want to tell IntelliJ to run the main method of "HelloWorld" instead of "com.company.Main"...

answered Mar 5, 2014 at 15:26

slartidan

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1 Comment

ThomasReiner Over a year ago

Yes but how to tell IntelliJ to run another main method?

Dodi · Accepted Answer · 2017-02-19 11:08:57Z

4

Go into Edit Configurations (see screenshot) and update your Main class path to be that of the changed package name. In my case, package is "thread" and in there I have a Main class:

answered Feb 19, 2017 at 11:08

Dodi

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Comments

Salah · Accepted Answer · 2014-03-05 15:21:22Z

3

You need to specify the package inside your class like this

package com.company;

public class HelloWorld {

    public static void main(String[] args) {
        System.out.println("hello world.");
    }
}

answered Mar 5, 2014 at 15:21

Salah

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1 Comment

George Tomlinson Over a year ago

Or just package company;, if com is the project name.

Batuhan B · Accepted Answer · 2014-03-05 15:30:33Z

0

Check these steps in order :

1) Is your file name and your class name is same ?

2) If you work on command line write javac yourfilename.java

3) Then java yourfilename

answered Mar 5, 2014 at 15:30

Batuhan B

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Comments

ROMANIA_engineer · Accepted Answer · 2014-11-25 13:41:10Z

0

First Set JDK PATH ..Then compile and run code

JDK Path Setting:

Follow the given steps below to set the PATH

After installing JDK, right click “My Computer” icon
Choose “Properties” from context menu
Click “Advanced” tab and the click ‘Environment Variable’
In the Edit windows, modify PATH by adding the location of the class to the value for PATH. If you do not have the item PATH, you may select to add a new variable and add PATH as the name and the location of the class as the value. For example, if you have installed JDK in C drive then path may be in the form C:\Program Files\Java\jdk1.6.0_12\bin
You will have to give your own path in which you have installed JDK.
Open Command prompt window, and run your Java code.

edited Nov 25, 2014 at 13:41

ROMANIA_engineer

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answered Nov 25, 2014 at 13:09

Filza Naser

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Comments

user4854199 · Accepted Answer · 2015-05-01 13:15:21Z

0

Change your main class from com.company.Main to the class you declared

answered May 1, 2015 at 13:15

user4854199

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