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Error message run I tried to run the hello world in java [message #1809203]

Thu, 11 July 2019 12:47

Sergeant Smiley

Messages: 1
Registered: July 2019

Junior Member

Why do I get this message when I tried to run a java program? What do I need to do so this won't continue to happen when I'm trying to run my Java program in Eclipse?

error occurred during initialization of boot layerjava.lang.module.findexception: error reading module: c:\coderepository\myproject\bincaused by: java.lang.module.invalidmoduledescriptorexception: myclass.class found in top-level directory (unnamed package not allowed in module)

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Re: Error message run I tried to run the hello world in java [message #1809213 is a reply to message #1809203]

Thu, 11 July 2019 16:47

Nitin Dahyabhai

Messages: 4435
Registered: July 2009

Senior Member

Declare your class as being in a package, using the package keyword, or don't have a module-info.java and cause it to be treated like a Java module.

_
Nitin Dahyabhai
Eclipse Web Tools Platform

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Re: Error message run I tried to run the hello world in java [message #1814019 is a reply to message #1809213]

Sun, 01 September 2019 19:15

MICHAEL DAVIS

Messages: 1
Registered: September 2019

Junior Member

while trying to run eclipse hello world I got the error

java.lang.module.InvalidModuleDescriptorException:

I saw an answer on the forum but I am new to eclipse and haven't programed in Java in a couple of years (BlueJ), in other words I didn't understand the answer. I need baby steps please.

Attachment: HelloWorld2.class
(Size: 0.56KB, Downloaded 1511 times)

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Re: Error message run I tried to run the hello world in java [message #1814050 is a reply to message #1814019]

Mon, 02 September 2019 10:13

Ed Merks

Messages: 33140
Registered: July 2009

Senior Member

No one can do anything with an attached .class file. Did you try declaring your class to have a package? This is a good reference:

https://www.vogella.com/tutorials/Eclipse/article.html

Ed Merks
Professional Support: https://www.macromodeling.com/

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Re: Error message run I tried to run the hello world in java [message #1855082 is a reply to message #1814050]

Wed, 28 September 2022 03:42

Nicolae FIERARU

Messages: 1
Registered: September 2022

Junior Member

I faced the same problem when I created the HelloWorld application for the second time (first time it worked, then I installed some other java IDE's). I run into errors while following step by step the instructions. I didn't know what to do and I reinstalled Eclipse. This did not help. I tried to reset to default most of the options and it also didn't help. Then I found this forum and I understood what was wrong. But it would be useful for the step by step instructions to include additional advice, such as what to type in the Package area in case it remains empty.

index.php/fa/42538/0/

Attachment: JavaHelloWorld.jpg
(Size: 486.81KB, Downloaded 31741 times)

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Re: Error message run I tried to run the hello world in java [message #1855102 is a reply to message #1855082]

Wed, 28 September 2022 15:08

Ed Merks

Messages: 33140
Registered: July 2009

Senior Member

I would be best to open an issue here with your observations and suggestions:

https://github.com/eclipse-jdt/eclipse.jdt.ui

Ed Merks
Professional Support: https://www.macromodeling.com/

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Re: Error message run I tried to run the hello world in java [message #1855105 is a reply to message #1855082]

Wed, 28 September 2022 17:06

Tauno Voipio

Messages: 742
Registered: August 2014

Senior Member

It sems that the cheat sheet is out of date. There should be a step for package creation after project creation and before class creation.

However, at least my 2022-09 JDT complains of missing package declaration as soon as the source is opened in the editor, see the red error mark at top left.

index.php/fa/42543/0/

Attachment: Screenshot 2022-09-28 at 18.53.52.png
(Size: 25.56KB, Downloaded 31673 times)

--

Tauno Voipio

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Re: Error message run I tried to run the hello world in java [message #1860928 is a reply to message #1809213]

Sat, 09 September 2023 19:39

THOMAS DOWNES

Messages: 4
Registered: September 2023

Junior Member

Thank you, however...
As a Java newbie, I find your answer challenging to understand operationally.
In other words, I am unclear of the implementation.
What are the concrete steps you are recommending?

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Re: Error message run I tried to run the hello world in java [message #1860930 is a reply to message #1809203]

Sat, 09 September 2023 20:05

THOMAS DOWNES

Messages: 4
Registered: September 2023

Junior Member

It's likely your project contains a file called module-info.java.
(This is a default file, but I don't know how to change the setting to not have it be automatically included in your project.)
Solution, right-click & delete the file ("module-info.java").
(See attached image.)
(Credit to Nitin Dahyabhai for his helpful suggestion!!)

Attachment: Module-package error (Hello World)--fixed.jpg
(Size: 34.17KB, Downloaded 466 times)
Attachment: Module-package error (Hello World)--fixed.jpg
(Size: 34.17KB, Downloaded 210 times)

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Re: Error message run I tried to run the hello world in java [message #1860931 is a reply to message #1809213]

Sat, 09 September 2023 20:07

THOMAS DOWNES

Messages: 4
Registered: September 2023

Junior Member

Thank you!! I deleted the file called "module-info.java", and it worked!!
(See attached image.)

Attachment: Module-package error (Hello World)--fixed.jpg
(Size: 34.17KB, Downloaded 200 times)

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Re: Error message run I tried to run the hello world in java [message #1860932 is a reply to message #1855082]

Sat, 09 September 2023 20:35

THOMAS DOWNES

Messages: 4
Registered: September 2023

Junior Member

Dear fellow newbie,
You are looking at the "Create New Class" dialog. Let's take a look at the "Create New Project" dialog instead. See image. As I mention in the image, the Create New Project dialog probably has "Create Module Info" (?) automatically checked.
Having "Create Module Info" checked seems to create extra work for the programmer. It seems to cause the compiler to expect that a "package" (whatever that means!) will be specified by the programmer (you & me).
When the new project is created, you'll see a file called "module-info.java" has been automatically added under the "src" folder.
That file ("module-info.java") is the problem. It puts the compiler into a "check package" mode (just a guess, as I don't really know what's going on).
Comment out the one-line command in that file, or right-click the file (from within the Project Explorer (?) and select "Delete" (to remove the module-info.java file from the project).
This worked for me, just within the last 20 minutes when I tried it out. Good luck!!

Attachment: Create a Java Project--p1.jpg
(Size: 146.20KB, Downloaded 167 times)

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