Why eclipse can't run other people's java file - java

When I press run, it appears. and none of those "Ant Build" works.
If I collect one of those, it shows
Build Failed
Reason:
Unable to find an Ant file to run.
This file is from other. It worked well on his eclipse. Every other my files run well.
This is from my eclips left side.
And this is the folder that is including the files from other.
Exam3, Exam4 are from friend which have probelm right now. I have to run it and check the result. But I can't.
*When I open these files using Visul Studio Code, it works well.
*I created new file "LL" in eclipse. and it has showed in same folder with Exam3 and Exam4. So the address for the file is correct I guess.
It's been few days since I started learning Java and eclips. So it can be ridiculous question. But I really need your help. Can you help me please?

You need to have a new folder where the file name is the same as the java public class name inside src of the new folder. You can do this by creating a new project within eclipseand file with the same class name.
So your file tree structure would look like LL > src > LL.java
And inside the java file provide the following in line 1
package LL;

Related

Creating an executable from a java project in eclipse

I have three classes, one of them is called Main and contains a main method, and no package. The IDE I use is eclipse. If I click File > Export and then select Java > Runable JAR File I'd expect to get a file that I can double-click and that'll run my program. However, that's not the case. If I click the resulting file nothing happens. I'm very new to this whole thing, so my questions are: Is this file even supposed to be clickable, or am I missing a step to run it? If that's the case, how to I convert the file to a .exe file (I really don't get this manifest-stuff, so please explain in detail how that needs to be done)? Basically: How do I create an executable (executable as in "works if i just click on it") file from three classes (with eclipse if possible)?
Edit: It's a console app.

Running .jar File Java 8

I've run .jar files before, but I've encountered a "different" situation, and I'm not sure what to do. I'd appreciate if someone could help me out.
Previously, I programmed with Java 6 and Eclipse Juno exported all my programs to runnable jar files. I'd get a .jar file that I could run by just double clicking on it. The files always looked something like this (note the jar file icon):
Recently, I wrote a program in Java 8 with Eclipse Luna (Release 4.4.0) and exported it to a runnable jar file, and I got something different (note the different file icon):
It no longer runs when I double click it. Instead, my computer uncompresses the jar, as it would a zip file. I tried running it from terminal. I cd'd to the directory and typed
java -jar graph3D.jar
I got the following error message:
Error: Unable to access jarfile graph3D.jar
After uncompressing the jar file, I found a folder named META-INF with the manifest file, MANIFEST.MF in it. It was the only file that seemed to resemble an executable file. Do I have to do something with that?
Could someone explain how I can run the second jar file graph3D.jar? Is it something new with Java 8, or something different about Eclipse Luna, or something else?
(Both programs run fine in Eclipse, by the way)
Thanks for your time and help.
Edit:
Below was the dialog box Eclipse displayed if anyone is interested.
Selecting "Use .jar;.zip" makes the filename "graph3D.jar;.jar;*.zip" .
Selecting "Use .zip" makes the filename "graph3D.jar;*.zip"
Selecting "Cancel" doesn't let you go forward.
You'd have to manually delete the extra file extension.
Somehow when you exported the file, the filters for the file dialog box (*.jar;*.zip) got attached to the filename, which is graph3D.jar;*.jar;*.zip, not graph3D.jar. Java can't find it because it doesn't have the name you supplied. Rename the file and pay close attention next time you export; either you fat-fingered something, or you're triggering a significant bug that needs fixing.
I recommend that you will access the build folder after you've built your project on the IDE under your project folder (in your workspace) and copy both the libraries folder and the .jar and post them wherever you want the program to be "installed", you'll then have an executable jar that should run smoothly without problems, just as I said don't forget the lib folder.
I think there is nothing new in Java 8 related with the running jar, I guess you need to check the the Eclipse export issues, it seems your classes are missing from your second jar file.

Eclipse LibGDX folder sharing

(4/15/2014 Still no working answer to the question)
I used gdx-setup-ui.jar to create my Android/Desktop/HTML5 program which I imported into Eclipse.
myprogram
myprogram-android
myprogram-desktop
myprogram-html
My program runs fine on desktop and android, but when I run it as html I get an error if all of my classes are not in the same myprogram>src folder, if I put it in a sub folder in src then the html5 does not seem to access the class. If I take my classes out of the folder and put them in the root of myprogram>src they work. How can I fix this?
I also notice that when I do a symbolic link to the asset folder manually(without gdx-setup-ui.jar) my Java application will not find the pictures etc unless I physically copy the asset folder twice. I made sure the folder path was exactly the same and it still wouldn't detect it unless I made a second copy of the pictures. Strangely the gdx-setup-ui.jar does this symbolic copy and yet it works for some reason.
This tutorial explains how to do it in Eclipse. And for completeness sake, here is how to do it using ant and IntelliJ. I hope this was useful. I will try the Eclipse one now...

Eclipse will not run programs or detect errors

My eclipse seems to be pretty screwed on my laptop. Whenever I load a program up from College, it does not detect the errors or anything. Also now when I attempt to run the program, it won't allow it; i'm given the message
unable to find an ant file to run
Anyone able to help me out?
1-Create a new project in Eclipse
2-After the project is created, look in the package explorer window pane on the left and right click on the src folder.
3-There are two methods for the next step, you could either add a New > Class, and then copy and paste everything from your old java file to the new class (make sure the class name is the same), or the better route would be to Import.
4-After clicking Import, select File System under the general folder. Click Next.
5-Browse for the java folder where your source files are located. Once you click ok, it will add all of the source files to the right pane.
6-Select which files you want to add and click Finish.
7-Now if you look at your Package Explorer window you should see the source files. Now just
compile them, and the error shouldn't appear and you can run them just like before.
By creating the new project, you're making sure Eclipse knows where your source files are located (in ./src) so that it can compile your code in that location.

Eclipse error with archived java projects "editor does not contain main type" [duplicate]

This question already has answers here:
Error: Selection does not contain a main type
(24 answers)
Closed 8 years ago.
I am receiving the errors: Editor does not contain main type, or, Selection does not contain main type when I import an archived Java project into Eclipse and try to run it. I have gotten this error on several different operating systems.
Archive Protocol
Export project
General->Archive File
All are selected: project folder, .classpath and .project
[x] save in zip format
[x] create directory structure for files
[x] compress contents of file
A Work Around That May Explain It... but how?!
I notice that when I import an archived project into an existing project (a blank Java project), The folder hierarchy is something like:
Project
src
bin
imported_project
bin
src
actual_code.java
Now, when I try to run actual_code.java, I get the above error. I discovered the following work around: if I drag actual_code.java and drop it into Project->src and then run it, it works.
This is a nice work around. However, I would prefer to be able to run the imported project without moving things around. Any suggestions on how to do this? It seems like it should be a trivial fix--it simply seems like the project isn't importing to where it ought to.
And yes...
I have tried every method I have come across to remedy this. That includes quite a few from this site and others: syntax, libraries, source path, restart eclipse, rearchive, different operating systems, different machines... etc.
The .java files are in the src folder before I archive them, and my build path seems correct.
You could import the archive as a Project instead of as files into a newly created blank project. Use Import > Existing Projects into Workspace. Then, use Select archive file.
You might want to put the src folder of your imported_project in classpath.
Right click on your project -> Properties -> Java Build Path -> Source -> Add Folder
I also faced the same error ajnd after reading above article i just drag/drop my class-file to src and new class-file generated in src is working fine .
I had the same problem after I New/Java Project then pulling src, docs, lib, examples, ... folders. I could not import it as an Eclipse project since the code is not an Eclipse project. The main is right there in the example code, but the IDE would find it.
The solution for me is deleting the project from the IDE, then recreating it with the Eclipse IDE. When recreating, the IDE cached all the sub-folders for me. Also, make sure you add the code onto the Java Build Path as Source using the 'Configure Build Path...' of the project.
Restarting IDE, closing then reopening the file didn't help me.

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