Java - Running my java program error

Question

I compiled my java program using "javac LabOne.java" and it complied suscessfully. Now in that folder there is a LabOne.java and LabOne.class as expected. But when i try to run the program by using "java LabOne" i get an error saying "Error: Could not find or load main class LabOne".

Please can someone assist me.

Code :

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package labone;

import java.util.Scanner;

/**
 *
 *
 */
public class LabOne {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {

        Scanner userInput = new Scanner(System.in);

        System.out.println("Welcome To The String Editor!"); 
        System.out.println(""); 
        System.out.println("Please choose what you would like to do by choosing one of the options below:"); 
        System.out.println("1. Input String");
        System.out.println("2. Print Current String");
        System.out.println(""); 
        int userOption = userInput.nextInt();
        String stringInput = new String ();

        switch (userOption) {
            case 1: stringInput = userInput.nextLine();
                    System.out.println(stringInput);
                    break;

            case 2: System.out.println(stringInput);
                    break;

            default: ;
                     break;
        }


        // TODO code application logic here
    }

}

Even if your OS (like Windows) is not case sensitive, Java **is**. — PM 77-1, Sep 21 '14 at 23:40
possible duplicate of [Java "Hello World" program running issue](http://stackoverflow.com/questions/7048423/java-hello-world-program-running-issue) — , Sep 21 '14 at 23:48
Your class is in a **labOne package**. Run as `java labOne.LabOne`, and run from the right directory, the one that holds the labOne directory. — Hovercraft Full Of Eels, Sep 21 '14 at 23:51

score 1 · Accepted Answer · edited May 23 '17 at 12:29

1

The problem is because your class LabOne resides in a package called labone. You are most probably inside the folder labone and you ran javac LabOne.java and it succeeded. But when you will try to run it using java LabOne it is going to fail.

The solution is cd up one level and execute:

javac labone/LabOne.java 

java labone/LabOne

and it will work.

This answer deals with a similar problem.

You can also try adding the package to the classpath but it doen't look like your class is dependent on other classes for now, so doing that might be an overkill.

edited May 23 '17 at 12:29

Community

1
1

answered Sep 22 '14 at 00:01

SJha

1,510
1
10
17

So the directory structure is labone/src/ ? – SJha Sep 22 '14 at 00:18
I got it to work by using the two statments above in the src folder. Thanks! – 45aken Sep 22 '14 at 00:18

Parth Satra · Answer 2 · 2014-09-21T23:46:18.033

0

The error says that the system cannot find the main method. There can be multiple reasons

Is the class labOne 'public'?
is the main method defined in the class 'labOne' and is defined public and static?
Is the class name same as the file name and is case sensitive so should be exact same?

If both the above is not the case then please also share the code to be able to answer that.

edited Sep 21 '14 at 23:46

answered Sep 21 '14 at 23:41

Parth Satra

513
2
16

1) public class LabOne { and for 2) public static void main(String[] args) { – 45aken Sep 21 '14 at 23:43
@45aken Now "LabOne"? That is yet another capitalisation. Please pick one and use it consistently. – khelwood Sep 21 '14 at 23:44
the file name is 'labOne.java' while the class name is 'LabOne' these are case sensitive and need to be the same. – Parth Satra Sep 21 '14 at 23:45
They are all LabOne. I just mistyped it here. – 45aken Sep 21 '14 at 23:48

score 0 · Answer 3 · answered Sep 21 '14 at 23:46

I'd start with sorting out file/class naming issues, accessibility operators and then eventually take a look at CLASSPATH. You can play with that path both in system environment settings and using -cp option while invoking java compiler. I strongly encourage you to share more details.

Java - Running my java program error

3 Answers3