How can I avoid this Ant Build error? - java

What is this ant build error in eclipse?
When I click the Ant Build I have the error message shown below.
Build failed
Reason: Unable to find an Ant file to run.
Could you please help me solve it?

Quoting from here
Create a new project in Eclipse
After the project is created, look in the package explorer window pane on the left and right click on the src folder.
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.
After clicking Import, select File System under the general folder. Click Next.
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.
Select which files you want to add and click Finish.
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.

Related

Unable to find or load Main Class in Intellij 2019.4

I have been at this problem for a few days now, don't know why it is still happening. I have tried other solutions that have been posted on stackoverflow but no luck.
Below the following code is from the book crafting interpreters in java.
In IntelliJ 2019.4 this error always pop up when I am trying to run the .jar file.
Error: Could not find or load main class com.jam.Jam
Caused by: java.lang.ClassNotFoundException: com.jam.Jam
I have built the .jar file and setting the main class as com.jam.Jam and the class path for the .jar file as /home/username/Jam-Programming_Language/src/com/jam/Scanner.Scanner.
This is the layout of my project directory.
The following solutions I have tried:
Solution 1
Open Project Structure
Select Modules, then click on the module for which you want the
dependency
Choose the Dependencies tab
Click the '+' at the bottom of the page and choose the appropriate
way to connect to the library file. If the jar file is already
listed in Libraries, then select 'Library'.
and
Solution 2
Go to the Project Structure, click on Modules, and click on your
Module
Choose the "Dependencies" tab
Click the "+" button on the right-hand side and select "Jars or
directories..."
Add the directory(ies) you want (note you can multi-select) and
click OK
In the dialog that comes up, select "classes" and NOT "jar directory"
Make sure you're using that Module in your run target
It had no effect apparently. Any clue on what I should do?
Edit: Uploaded wrong screenshot, replaced screenshot.
Thanks to CrazyCoder for pointing out the errors in my project (silly mistakes). It seems that after I have resolved those mistakes.
I had to follow the solutions I have posted then rebuild the .jar file.
Afterwards I need to mark the src folder as a source root folder (right click folder -> Mark Directory as -> sources root)
Edit Configurations if pointing to wrong main class.
Set Project compiler output (File -> Project Structure -> Project) to a folder designated to hold the output (any folder basically in or outside the project).
The error says, it is trying to run: com.jam.testfile. Your class is called: com.jam.Jam.
Click the dropdown where it shows "testfile" with a little red X on it. Select "Edit Configuration." For the "Main class", select "com.jam.Jam". That's it!
BTW, the little red X means there is some problem with your configuration.

splashscreeen not working in netbeans IDE for java?

slash screen tutorial
By following the above tutorial i did the following things
step1: created a new project named SplashScreenTest
step2: include the gif file named laoding.gif in the project
step3: added a new JFrameForm to project with the name StartGUI.java
step4: rightclick the form->properties->code->form size
policy->generate resize code
generate position ->untick
generate size ->untick
generate center ->tick
step5: replaces "Nimbus" with "Windows" inside
step6: right click SplashScreenTest->properties->VMoptions
-splash:src/AppPackage/loading.gif
step7 : open Manifest.mf write "SplashScreen-Image:
AppPackage/loading.gif"
step8: set main class to AppPackage.StartGUI
Now as soon as i hit the clean and build button it returns an error
"existing manifest file is invalid"
May I know what is the correct way to achieve my objective?Maybe this question too basic, but i did't find any suitable solution.Please Help me out.
I'm kind of weirded out by the hoops you are jumping through, Netbeans actually provides support for the splash-screen via the Project's Properties
Right click the project node...
Select the "Application" properties...
Browse for the splash screen image to be used...Netbeans will automatically included within the compiled jar file...
Clean and build your project...

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.

How to take package .java files into a Eclipse Project

I've got a copy of a java package, with example implementation. The package is in a structure called com.java.project (folders, containing myriads of .java files) and there's also a few example files (example1.java, example2.java)
The example files have 'import com.java.project' calls in them, that's all well and good. However, I can't seem to work out how to get Eclipse finding the package contents (currently returns "Type not found" for any calls to the project objects.
I've tried placing the com structure in the same level as my example1.java, but that doesn't work. I have read that I need to compile the package into a .jar to get it to work w/Eclipse, but that doesn't seem to want to behave, none of the files compile.
In Eclipse you can right click on the Project Explorer and select "New -> Java Project"
Then you can import your java files by right clicking your project, selecting import from file system. If the class file shows an error, open the class file, the class name should have red curly braces, click on the error tick mark and Eclipse will give you an option to move the file to the correct package which in turn creates the folder structure for you.
1.Can you do a check on the build path of your Java project? (Right-click the project -> Properties -> Java Build Path -> Source tab), and see if the root folder contains the code is properly specified here.
2.Maybe a Project->Clean will help as well.
Hii,
Just Create a new project with File -> New menu
you need to open Java Perspective and there you will find a package named "src" you need to copy your "com" directory and paste it at the src folder.
I hope this will work for you.

Adding .class files to an Eclipse project

This is a total newbie question, but I can't figure it out so I figured that I would ask it here and see what happened.
Here's the problem: For my java programming class, we are supposed to download a .class file created by our instructors containing a custom-made class with methods that we are supposed to use in an assignment. I already know all of the code to create the class within my actual program, but I can't figure out which directory to place the .class file in. I have tried the src and bin folders inside the project directory, and even placed it directly into the project directory, but nothing seems to work. My instructors say to just put it in the same directory as my java program, but they are using jGRASP. What am I doing wrong?
You can place the class file anywhere, just be sure to add its directory to your project's build path. Right click on the project, then properties at the bottom then build path, til you find add class folder.
You have to create a project, or open your project if you have it already, then, while you are in the Java view, select File > New > File. It will open a window, you can create your file there and choose in which project folder do you want to put it. If in that window you press the button "Advanced >>" it will give you the option to "Link to file in the system", check it, and then you can browse your folders to the downloaded file.
I don't know if this solves your problem, it's what I understood from your question.
Your instructors class file must be in the build-time and the run-time class paths for your project to use it. Instructions assume that you are on a PC.
Run-time class path setup
Create a directory (perhaps C:\JavaRoot\classes). I will refer to this as the Classes directory.
If one does not already exist on your PC, create an environment variable named CLASSPATH
Add the Classes directory to your CLASSPATH envoronment variable
Download the class in question and put it in the Classes directory.
Build-time class path setup
Right mouse on your project in eclipse.
Select "Properties".
Select "Java Build Path".
Select the "Libraries" tab.
Click the "Add a Class Folder" button.
Browse to and select the Classes directory you created during "Run-time class path setup" above.
Click the "OK" button
For Eclipse use the following:
Project > Properties > Java Build Path > Libraries (Tab) > Add External Class Folder (Button)
If you have a configured project in Eclipse and you manually added a Java class file in some of the project directories, you just need to refresh the project for Eclipse to recognize it:
Right click in your project (in "Project Explorer" view) -> Refresh

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