Thread: Netbeans vs. reality conflict

Greetings folks. Here's one of those questions that seems to have been asked a million different times in a million different ways by a million different people, but none of those answers seems to be relevant to me.

Ok, so I am just starting out with Java, using the Oracle Java tutorials. I used Netbeans IDE to create the simple HelloWorldApp program, compiled it to a .class file, and then it works fine in Netbeans using the Run command there, but I wanted to see if it would work from the command line (because not everyone's going to have Netbeans but they still might want to run my program). Surprise surprise, it didn't work.

So now I will provide all the pertinent data. First, the program code:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package helloworldapp;
 
/**
 *
 * @author //my name deleted
 */
public class HelloWorldApp {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

Screenshot of error:

Java-error.jpg

There you go lol. Thanks in advance!

-summit45

try
HelloWorldApp instead of helloworldapp

Originally Posted by derekxec

try
HelloWorldApp instead of helloworldapp

I have, multiple times, and it doesn't work. Same result.

-summit45

Originally Posted by copeg

Ditch the IDE (eg Netbeans) for the moment and start from the beginning - compile and run all via the command line.
See Lesson: The "Hello World!" Application (The Java™ Tutorials > Getting Started) for the appropriate OS instructions
The class you posted is contained within a package, which is an important topic in and of itself, but makes compiling and running code more complex for someone trying to learn topics that need to be learned beforehand.

Well, I appreciate that, but I'd rather understand why this isn't working when there is no legitimate reason why it shouldn't be.

-summit45

There is a legitimate reason. Saying there isn't because you don't understand it or don't want to take the advice given is a bit odd.

As copeg said, your source code specifies that it is in a package. The use of packages adds complexity - especially to working from the command line - not typically introduced at the HelloWorld level. To address that complexity, back up a directory level, to "classes", and type:

java helloworldapp\HelloWorldApp

Good luck!

Originally Posted by GregBrannon

There is a legitimate reason. Saying there isn't because you don't understand it or don't want to take the advice given is a bit odd.

There is always a "real" reason, if you will, why any bug exists. The legitimacy of it is an opinion. I find it silly for a program executor to be this finicky.

As copeg said, your source code specifies that it is in a package. The use of packages adds complexity - especially to working from the command line - not typically introduced at the HelloWorld level. To address that complexity, back up a directory level, to "classes", and type:

java helloworldapp\HelloWorldApp

Tried. I've tried it before because I found this same suggestion on a Google search, except "java helloworldapp.HelloWorldApp" (in my case) was/would have been recommended. Tried again now with a slash instead. Same error.

-summit45

Then something else is going on. As you've (kind of) said, this isn't that hard, but the steps to compile and run a Java program have to be done exactly right with the files in their proper places. IDEs do things behind the scenes that, until the user understands the steps well, may make it difficult to pick up where they've left off and complete the necessary steps correctly.

I know you've already pooh-poohed copeg's suggestion as non-productive, but I recommend you reconsider. Take the same HelloWorld program, first without the package declaration, and a simple programmer's editor like NotePad+ or even Geany, and get it running from the command line. Once you've mastered the simplest case, well documented in tutorials all over the web, put the same source file in a package, note the differences in the resulting directory structure (or not), and get that running from the command line using the right commands correctly applied, perhaps one or a variation of one of those you've already tried.

It's a good exercise, and you should be a bit smarter and more confident in the whole compile/run process once you're done. You might even learn a simple programmer's editor well enough to become confident in its use and recognize that the skill is an attractive alternative to firing up one of the large IDEs which can be more trouble than they're worth sometimes.

Good luck and please keep us posted.

Originally Posted by GregBrannon

I know you've already pooh-poohed copeg's suggestion as non-productive, but I recommend you reconsider.

That's a harsh way to put it. I didn't "pooh-pooh" it. I understand it, and I understand it may be useful to drop the IDE and learn the command line better, but I just was hoping to get an answer about what is actually going on rather than only "just drop it and do this instead."

But apparently the error is too complicated for even the experts of Java Forum to understand. Which is why I say, it's illegitimate.

Well, I'll give the command line way I try then I suppose. Thanks for the advice.

-summit45

Thank you, helloworld! That did it. Which is strange because I thought I tried that before, but maybe I got the capitalization wrong.

Much obliged.

-summit45