Add a project with a static class to another project in Eclipse - java

OK, this might be a pretty basic question so please sorry.
In Eclipse, I have a project with some utilities, let's call it Utils.
Something like
public class Utils {
public static void doSomething() {
// do something
}
}
I want to use this project as a library for many my other projects, for example my project "MyProject"
After I assure that there are no syntax problems in Utils, I keep it open in the UI and open also MyProject.
In MyProject I go to Properties -> Java Build Path -> Projects -> Add and add Utils.
Now I should be able to see Utils.doSomething() when I press CTRL-Space and use it in the code, but this is not the case.
What am I missing?
I have been going round and round to find how but could not find a solution.
Thank you very much
EDIT:
I think I tried all the usual problem-solving solutions like cleaning the projects, restarting Eclipse, recreating ex-novo Utils, rebuilding and automatic imports.
For this reason I think that the real problem is not Eclipse but me, I am missing something that I don't understand.

I think I solved it.
The Utils (Android) project had the public class in the "default container" that had no name, probably that was the reason.

Related

Errors with trying to make a minecraft plugin (Ecilpse)

I have imported the latest version of spigot-api to my project, but when i write import org.bukkit.plugin.java.JavaPlugin;, I get a error saying
The type org.bukkit.plugin.java.JavaPlugin is not accessible.
I need help.
Thank you.
RESOLVED: Switching from JavaSE-12 to JavaSE-1.8 worked
First of all, make sure you imported it correctly: Right click on your project > Properties > Java Build Path > Libraries > Add External JARs...
If you already did that, make use of Eclipses quick fix feature. Add extends JavaPlugin to your public class, so it looks like this:
//JavaPlugin will be flagged as an error
public class MainClass extends JavaPlugin {
...
}
Now hover over JavaPlugin, a small menu should pop up, suggesting possible solutions with the first one being Import 'JavaPlugin' (org.bukkit.plugin.java), Click on it and it should import the JavaPlugin object
If both solutions don't work, I'd either suggest updating Java or use Maven, it manages your dependencies and there should be Eclipse/Maven addons for Minecraft plugin developers, to help make the start easier

How can I create and Import Libraries in Netbeans - A Full Documented Q

It's me again. So here's the deal, I still don’t really grasp if I am doing something wrong.
I am trying to create my own Personal Library, in which I have certain string methods and so on.
I’ve started by creating a new Project as a Java library:
Then I've added a package to that library:
After that I've created a class in said package:
Here the code of my class:
And cleaned and built that Class//Library. Run -> Clean and Build
And afterwards created the JavaDoc Run -> Generate JavaDoc(MyTestLibrary)
After doing this i decided to add my newly created Library to the Libraries under Tools - > Libraries:
After that I’ve added a new Library (bottom right) and named it TestLibrary:
SO decided to add the .jar File first. I clicked on the “Add JAR/Folder... ” Option and searched for my Projekt Folder (from MyTestLibrary) and went in to the “dist” folder and selected the .jar file:
After that I’ve added the “src”-Folder in “Sources” and the “javadoc”-Folder in “Javadoc”.
After i was finished it was time to create a new Project, to be precise a new Java Application, and try to import my freshly created library. I rightclicked on Libraries and clicked on “Add Library...”:
And imported my Test Library and adding it:
Happy that I've added my Library to my application I decided to import it
import TestPackage.TestClass;.
If I try
public static void main(String[] args)
{
TestClass.
}
The only suggestion is TestClass.class and not TestClass.TestMethod.
Why can't I access the methods of the “TestClass” directly?
How can I see them?
I've tried being as specific as possible. I hope this time I can fully understand what is going on and why I can't access them.
The solution was fairly simple and obvious.
To access the methods without the need of creating an instance of the class i just had to declare them static.

Added jar in BootStrap location is not reflecting in My Classes using Eclipse

Please help me to understand whats wrong with this.
I added a jar in a BootStrap location of
jdk(C:\Program Files\Java\jdk1.6.0_27\lib\ext) and in jre(C:\Program
Files\Java\jre1.6.0_22\lib\ext)
but jar class is not reflecting while try to invoke methods or classes added by jar in Eclipse.
Also help me to know where I can see the printed things by static block by Logs.......
Below I included the class I used to create the JAR.
package test.classloader;
public class BootStrapTest {
static
{
System.out.println("BootStrap Jar is Loaded....................");
}
public static String checkClassLoader()
{
return "This is BootStrap Class Check ClassLoader";
}
}
I am going to take a stab at the reason behind why you think you need to do this. Excuse me if I am incorrect but you provide vague information and it is unclear what your question is.
If you need missing Java EE libs (or other 3rd party libs) in Eclipse, add one of the sofware REPOs (to your Eclipse software manager) listed on this URL and then install the Java EE libs from it: http://download.eclipse.org/tools/orbit/downloads/
Or, use Maven as a build tool and add the appropriate dependency to download the lib that your project needs.

Error: Could not find or load main class in intelliJ IDE

I'm a beginner in Java and am trying to run my code using IntelliJ that I just installed as my IDE with JDK 1.7. The following piece of code keeps does not even compile and keeps giving me the error:
Error: Could not find or load main class libTest
Code
import java.lang.Integer;
import java.lang.String;
import java.lang.System;
import java.util.*;
class book {
private String name = "trial";
private int bookCode=1;
private int issued=0;
public void Issue(){
if(issued==0) {
issued=1;
System.out.println("You have succesfully issued the book");
}
else {
System.out.println("The book is already issued. Please contact the librarian for further details");
}
}
public int checkCode() {
return bookCode;
}
String readName() {
return name;
}
public void setName(String newName){
name=newName;
}
public void setBookCode(int newCode){
bookCode=newCode;
}
}
class library {
private ArrayList books=new ArrayList();
public void getList(){
for(int bk:books){
String bName=books(bk).readName();
System.out.println((bk+1)+") "+bName);
}
}
}
public class libTest{
public static void main(String[] args){
library newLib= new library();
System.out.println("code working");
}
}
Is there any change that i have to make in the compiler settings?? Or is it the code.
This might help:
1) "Build" menu -> "Rebuild Project".
Sometimes Intellij doesn't rewrite the classes because they already exist, this way you ask Intellij to rewrite everything.
2) "Run" menu -> "Edit configuration" -> delete the profile -> add back the profile ("Application" if it's a Java application), choose your main class from the "Main Class" dropdown menu.
3)"Build" menu -> "Rebuild Project".
If none of the above answers worked for you, just close your IntelliJ IDE and remove the IntelliJ IDE file and folder from the root of your project:
rm -rf .idea *.iml
Then open the project with IntelliJ. It must work now.
For me the solution was to fix the output directory under project settings. Before I was using just "target" for the Project compiler output. Instead I updated it to have a full path e.g. D:\dev\sigplusjava2_68\target
I had this problem and I tried everything under the sun that I could think of and on this site.
None of my Java classes were being picked up after I pulled from a remote branch. All the classes had red Js by their names in the Project Hierarchy, not blue Cs.
In the end, I tried to follow this tutorial and a few steps in tried something not described and fixed the issue:
https://www.jetbrains.com/help/idea/creating-and-managing-modules.html
Here's what I did:
Goto File | Project Structure, or press Crtl+Shift+Alt+S
Select Modules under the Project Settings section.
In the Sources tab click Sources on the 'Mark as:' line.
Click the Apply button.
For some reason, all my classes then had blue C's.
Someone with a better understanding of how IntelliJ and/or IDE's might be able to explain the phenomenon, but all I know is now it can see all the classes and more importantly the main one, and run.
Invalidate cache and restart your IntelliJ, it worked for me.
Explicitly creating an out folder and then setting the output path to C:\Users\USERNAME\IdeaProjects\PROJECTNAME\out
seemed to work for me when just out, and expecting IntelliJ to make the folder wouldn't.
Also try having IntelliJ make you a new run configuration:
Find the previous one by clicking
then remove it
and hit okay.
Now, (IMPORTANT STEP) open the class containing your main method. This is probably easiest done by clicking on the class name in the left-hand side Project Pane.
Give 'er a Alt + Shift + F10 and you should get a
Now hit Enter!!
Tadah??
(Did it work?)
File > Project Structure > Modules > Mark "src" folder as sources.
This should fix the problem. Also check latest language is selected so that you don't have to change code or do any config changes.
I know this was asked a while ago, but I was just stumbling over this issue and thought my findings might help others. As pointed out, the error message is basically a result of the out folder. That's because, when you're trying to run the program, it compiles the code first, and puts the compiled result to the out location, and then it tries to load the compiled code from the out location. If the compiled code is not in the location expected, you'll get the error.
The point I'm particularly wanting to share is that some times, the code is not compiled (built), even though your run configuration specifies "Build" in the "Before launch" section of the configuration panel.
When can this happen?
One situation that can cause this to happen is if you're using modules and you manually delete the module out directory. For example, if I have a module named "foo", there should be a directory named foo under out/production. If you manually delete it, the build system may not know that it needs to be rebuilt.
Even worse, if you select Build | Build module 'foo', it still may not rebuild the module. If that's the case, you should select a file in the module, for example 'bar.java' and then select Build | Recompile 'bar.java'. Now the out directory out/production/foo should be restored.
Since IntelliJ typically knows about any changes going on, this surprised me, and took me a little time to figure out, so I thought I'd share.
Check your class module : I have encountered this problem with intellij :
I have a maven multi-module project, the problem is that i runing a class which not exist the module within the configuration, so my problem is fixed by setting the right module ("edit configuration" -> "use class of module")
may this help you
I had to mark the "src" folder as "Sources". After restarting IntelliJ and rebuilding the project I could run the project without further issues (see screenshot).
Edit: You can access the "Project Structure" tab via File->Project Structure or by pressing Ctrl+Shift+Alt+S.
I ran into this problem when my Java class was under src/main/kotlin. After I moved it to src/main/java, the problem was gone.
I have faced such problems when the class is in the default folder, i.e. when the class does not declare a package.
So I guess using a package statement (eg. package org.me.mypackage;) on top of the class should fix it.
Open Modules Tab (Press Ctrl+Shift+Alt+S). I had two modules under one project. I've solved the problem after removing the second redundant module (see screenshot).
After creating your project in intelliJ, try running the following command:
mvn package
I have tried all the hacks suggested here - to no avail. At the end I have simply created a new Maven application and manually copied into it - one by one - the pom.xml and the java files and resources. It all works now. I am new to IntelliJ and totally unimpressed but how easy it is to get it into an unstable state.
Invalidating cache didn't work.
I edited the main class java file with a dummy change and ran it. It worked.
In my case the problem seemed to be related to upgrading IntelliJ. When I did this I overwrote the files from the old IntelliJ with the files from the new IntelliJ (2017 community to 2018 community). After that all of my projects were broken. I tried everything in this thread and none of them worked. I tried upgrading gradle to the latest version (4 to 4.8) and that didn't work. The only thing that worked for me was deleting the entire IntelliJ folder and reinstalling it. All of my projects worked after that.
I have tried almost everything suggested in the answers here, but nothing worked for me.
After an hour of just trying to run my application, I noticed that my project's path included non-ASCII characters (Arabic characters). After I moved my project to a path with no non-ASCII characters, it executed just fine.
Goto File-> Invalidate Caches and Restart .
Else delete rm -rf .idea *.iml
and restart InteliJ
You can run the maven command on the pom.xml file in your project directory:
mvn clean install
For me - i tried few of the options above, did not work. Then i just renamed my Application class and that probably forced intelliJ to build a fresh jar and error message started to change. Then i renamed it back and it worked.
Mark the directory as a source directory. Opened via Ctrl+Shift+Alt+S
modules.xml with wrong content, I don't know what's matter with my IDEA.
I inherited a bunch of .JAVA files from elsewhere and couldn't figure out how to get them to work in any IDE. Ultimately I had to go to the command line where the Main.JAVA file was and run javac Main.java. This created a bunch of .CLASS files. The IDE's were then able to figure out what to do.
I got this error when using Scala/SBT. IntelliJ could not find the main class, even though everything was set up correctly.
My solution: delete the <user>/.sbt/<version>/plugins/target folder, then restart IntelliJ.
You probably would have specified a wrong package and the package hierarchy would not be right. Look below
The ide would highlight the wrong path in that case.
I'm using IntelliJ with Spring and my main class is wrapped in a JAR.
I had to mark the 'Include dependencies with "Provided" scope' in the Run/Debug configuration dialog
We are at File/Project Structure..
Answer might be:
Folder indicated as "content root" needs a child folder where the code is.
Plus find the button that marks code as excluded and not.
Not to be confused with tickbox that states excluded without telling in what phase and what**
Is it compiler exclude or runtime exclude? You are doomed to test and lot.
So no that tickbox but icons and colors.
As an idea we need to crack how it was originally thought to work. They never got it to work in first place and started add things in premature codaculation style.
It has been so many years and you cannot expect any improvement.
But as cure we can hack out some way to get it right every time.
Another thing you can check here is the actual command that is being passed to the JVM and make sure it looks OK. Scroll to the top of your Run console, it should be the first line.
Spaces in your Run Configuration VM Options field will malform the app startup command and can result in this error message
-DsomeArgument="arg with space must be quoted"
I am working with Kotlin but am guessing the problem is the same. I would start a project, create a single file and add main to it and the IDE couldn't find the main.
I tried the things in this list and none worked. I finally mentioned my frustration on one of the IntelliJ pages and was contacted. Of course, it worked fine for IntelliJ. After a couple of days back and forth, I noticed that the highlight function wasn't working and mentioned that. It turned out something was wrong with the IDE settings. I still don't know specifically what was wrong but the fix in my case was to reset the IDE settings. File->Manage IDE Settings->Restore Default settings.
After this, the green triangle start icon became visible to the left of my main function and things continued to work normally for subsequent projects.
Thanks to Konstantin at JetBrain's support for his patience.

Eclipse returns error on run: "java selection does not contain a main type"

I am unable to run the following code in Eclipse (Eclipse IDE for Java Developers, Version: Indigo Service Release 1, Build id: 20110916-0149), and I think that I may have a configuration problem in Eclipse (but I do not know what or where):
class Saluton {
public static void main(String args[])
{
String greeting = "Saluton mondo!";
System.out.println(greeting);
}
}
I am also running against Java 6 (1.6.0_29-b11-402) on Macintosh 10.7.2.
When I run this, I get the error:
"java selection does not contain a main type"
but I am pretty sure that my class is written correctly...? I have looked this error up, and cannot explain this problem so far.
TIA for any thoughts or opinions!
I think you have to make your class public, otherwise it won't work?
EDIT: My previous answer was incorrect. The JLS says you can declare arrays with the brackets at either end. See here for some examples. My mistake.
Have you verified your configuration in Eclipse such that it knows where to find the Java compiler, and a JVM? You can check the project-specific libraries by right clicking the project and going to Properties, Java Build Path
You can also check the JRE's installed by clicking Window, Preferences, Java, Installed JREs. Make sure the JRE you wish to use is listed here and that the path is correct.
Another solution (simple and direct):
In Eclipse: File -> Restart
Right click your class Saluton and choose Run as --> Java Application.
It should work.
Ok, so I'm a fellow noob, and I came here because I had this problem. I checked all my class paths and everything, and they were correct. I had actually been putting all of my files in the JRE System Library Folder, instead of the source folder. I'm not sure if this was you'r problem, but it seemed to work for me when I moved the code files into the src folder.
I took the long way around to solve this; eventually I created a package within my project and added my source code to that package and it compiled and ran! I am learning that Wizards rule!
It will work if you make your class as public !

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