We Keep Coding

Using CHelper plugin in IntelliJ for a coding contest

I quite recently discovered a coding site, with coding contests : CodinGame, and in order to solve the problems, we have to hand them over only one file with a main (in the following example, the class Player), and if other classes are needed, we include them in this file.
For this purpose (and seen to be working for another coding site), I have downloaded intelliJ and the plugin CHelper in order to put all the source files into one java file (it is supposed to be the purpose of the CHelper plugin). The problem is: I don't understand how to use/setup this plugin for my coding site. I know it should work because another user of this site has already used the plugin for this purpose.
What I want
For a more detailed example of what I want, here is the class with a main:
// Class Player in file Player.java
public class Player {
public static void main(String[] args) {
System.out.println(new Cell(1,2).toString());
}
}
And this class Cell is in another java file :
// Class Cell in file Cell.java
public class Cell {
int x,y;
public Cell(int x, int y) {
this.x = x;
this.y = y;
}
public String toString() {
return "["+x+","+y+"]";
}
}
And I would like the plugin to merge the two (or more) java files in order to have this :
// Generated : 2 files merged into one file: Player.java
public class Player {
public static void main(String[] args) {
System.out.println(new Cell(1,2).toString());
}
// Class Cell merged in this file
public class Cell {
int x,y;
public Cell(int x, int y) {
this.x = x;
this.y = y;
}
public String toString() {
return "["+x+","+y+"]";
}
}
}
What I achieved
I installed IntelliJ correctly, and downloaded the CHelper plugin.
I installed the toolbar menu buttons linked to TopCoder (the site that this plugin is expressly made for), but the Launch TopCoder button throws a RuntimeException : cannot run program .../javaws no such file.
With some tasks downloaded from TopCoder, I succeeded in merging 2 files into one : TaskA.java into Main.java (with templates downloaded)
What would be ideal
If an Eclipse plugin could work like what I want, I would be very happy to know of it. In fact, that was what I was looking for at the beginning of my search, and I only found some plugin for the IntelliJ IDE.

So I finally found a way to do what I wanted: the guy who had done it shared me a link to the help I needed.
I am going to sum it up specifically for CodinGame here.
I- Toolbar buttons
The important buttons to add to the menu toolbar are
create new task
modify task
delete task
Edit project settings
Now, we have some buttons in the red rectangle :
II- Edit settings
Then we have to edit project settings :
set the default directory to your default package
output directory is for the generated source file
III- Create task
Next thing, we have to create a new task (green "+" button) and set it up using the advanced option. We add the tests input and known output with the button Edit tests. We say we want the generated file to be called Solution.java, and the class where we are going to write is going to be called CGXFormatter.java
We now have two files which have appeared in our package .../puzzle :
CGXFormatter.java with a method solve, which is where we are going to read the input and give our answer in the output
CGXFormatter.task, which contains the info on the test cases, etc. in order for the plugin to generate the source file
IV- Write your solution
For example, we are just going to print "This is the result" in our CGXFormatter class (but we could have created another class file and called it, it would have worked by copying the definition of the class in the generated solution class). Like this :
package com......puzzle;
import java.util.Scanner;
import java.io.PrintWriter;
public class CGXFormatter {
public void solve(int testNumber, Scanner in, PrintWriter out) {
out.println("This is the result");
}
}
V- Generate the solution
Last step: click on run. Then we have the directory generated which is created, and in it, we have the Solution.java file newly generated. We can read this :
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;
/**
* Built using CHelper plug-in
* Actual solution is at the top
*
* #author XXX
*/
public class Solution {
public static void main(String[] args) {
InputStream inputStream = System.in;
OutputStream outputStream = System.out;
Scanner in = new Scanner(inputStream);
PrintWriter out = new PrintWriter(outputStream);
CGXFormatter solver = new CGXFormatter();
try {
int testNumber = 1;
while (true)
solver.solve(testNumber++, in, out);
} catch (UnknownError e) {
out.close();
}
}
static class CGXFormatter {
public void solve(int testNumber, Scanner in, PrintWriter out) {
out.println("This is the result");
}
}
}
VI- Last step
Okay, there still remains a little problem: in CodinGame, the solution class should not have public in front of it, so just put class Solution instead of public class Solution and you're done.
If you want, you can also put it in a script to do it automatically with a multirun (plugin to install in IDEA, also).
That's it, you're done.
VII- Edit Octobre 2019
If the plugin complains about not finding a net.egork.... class, you can add these steps that I found here
Update Intellij IDEA to the latest version. Secondly, you go to File
-> Settings... -> Plugins and search for the chelper plugin. It is required to run the task run configurations, and it supplies you with
the buttons on the toolbar, too. After you have done that, you should
be getting the error about impossibility to find and load class from
net.egork... Now you go to the jetbrains plugin site, search for
chelper plugin there, and download the latest zip archive. After
unzipping it, go to File -> Project Structure... -> Libraries -> + ->
Java, select recursively the folder you just unzipped until you get to
a bunch of jars that contain that missing class in the error. After
you have added those jars to your classpath, along with JDK, it should
be enough
As a side note, I remarked that the out.println didn't work as I intended (I don't know why), so I replaced it by System.out.println instead of using the proposed out object in the solve method.

Java Swing window not appearing in Eclipse

I have this code below to display a window using Java Swing. The problem is when I run the code in eclipse the window does not show. When I export the file as an executable JAR file and run it it works. Is there a bug with eclipse that prevents it from running it from there?
What am I missing?
package com.gui;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.BorderLayout;
public class Calculator {
private JFrame frame;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Calculator window = new Calculator();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Calculator() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
//frame.setBounds(100, 100, 450, 300);
frame.setSize(400, 200);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel lblNewLabel = new JLabel("Hello World");
frame.getContentPane().add(lblNewLabel, BorderLayout.NORTH);
}
}

Some projects created by Eclipse/WindowBuilder in macOS have this window-not-showing-up problem.
When an app is created through New > Project > WindowBuilder > SWT Designer > SWT/JFace Java Project, the new project automatically includes several extra jar files in classpath. Certain jar file(s) trigger eclipse to use special arguments (-XstartOnFirstThread) in the command (ps aux | grep to find out) when starting the application, and startOnFirstThread is giving us the problem here. AFAIK, -XstartOnFirstThread is added only in MacOS.
Solution 1: don’t use “WindowBuilder > SWT Designer > SWT/JFace Java Project” to create the project. You can just create a regular java project, and add the stuff you need.
Solution 2: remove the jar files. Right click on project > Properties > Build Path > Configure Build Path > Libraries, remove org.eclipse.swt (removing this one suffices in my case, there might be others in your case).

I had the same problem, and this is what worked for me (after the help of some folks on stackoverflow).
It turns out I had a library problem. I had had imported all the jars in the .lib directory from jfreechart. In reality only two were needed and some unnecessary ones were labeled swt and experimental. Once I removed all the ones that were not needed, did a clean, and rebuilt, everything worked fine.
Oddly, changing the order of the jfreechart library (which included the conflicting jars) to the bottom did not help, the extra jars had to be removed.
Not a jfreechart issue, obviously my own library import issue. So I suggest you try to remove some of the libraries that may be conflicting, then clean, build, and run again. Good luck.

Had the same issue and the root cause turned out to be the extra .jar in the build path(using macOS). For me, it worked after removing the org.eclipse.swt.cocoa.macosx.x86_64_3*.jar too. part.

ListResourceBundle and MissingResourceException

I'm working on a project that involves loading up a ResourceBundle. More explicitly, I've created a class that extends ListResourceBundle. The class is called Resources.java. It compiles fine and everything, but the MissingResourceException keeps popping up every time I try to load up the class:
All my source files are in package chapter31. When making this call with or without the "chapter31" in the string, always results in a MissingResourceException. My IDE is Eclipse. I've been playing around with this one problem for two days. I even tried changing the version of Eclipse. I'm at the end of my rope. What can I do in Eclipse to ensure that the getBundle() method can see the class. I don't know how it can miss it. It's in the same package! Please advise.
Alikas
package chapter31;
import java.applet.Applet;
import java.applet.AudioClip;
import java.util.ListResourceBundle;
import java.util.ResourceBundle;
import javax.swing.ImageIcon;
public class Resources extends ListResourceBundle {
Object contents[][];
public Resources() {
AudioClip clip = Applet.newAudioClip(getClass().getResource("/E31_10/audio/us.mid"));
ImageIcon image = new ImageIcon(getClass().getResource("/E31_10/image/us.gif"));
contents = new Object[3][2];
contents[0] = new Object[] {"clip", clip};
contents[1] = new Object[] {"icon", image};
contents[3] = new Object[] {"delay", new Integer(68000)};
}
protected Object[][] getContents() {
return contents;
}
public static void main(String[] args) {
ResourceBundle res = ResourceBundle.getBundle("chapter31.Resources");
}
}

The MissingResourceException is misleading here. Your problem may be caused by two other problems:
The resources in the following two lines cannot be found:
AudioClip clip =
Applet.newAudioClip(getClass().getResource("/E31_10/audio/us.mid"));
ImageIcon image = new ImageIcon(getClass().getResource("/E31_10/image/us.gif"));
If the first one is not the problem, there is a second problem:
You have a wrong array index contents[3] which will cause ArrayIndexOutOfBoundsException and this will also cause the misleading MissingResourceException to be thrown. If you can find this exception in your exception stack trace, your problem is here. Change it to contents[2] will solve the problem.
Note: The reason you are seeing MissingResourceException is ultimately caused by the class loader cannot create an instance of the Resources class due to the problems pointed out above. If you had put the contents array initialization codes in a separate method instead of the constructor, you may not get this exception at the object initialization phase. Of course, other exceptions will pop out later when you try to call getObject method.

Are you trying to load a message properties file called "chapter31.Resources"? If so then in Eclipse you can try the below:
Click on "Debug Configuration..."
Find the launcher you are using to execute the main method for Resources
Click on the Classpath tab
Click on "User Entries" and then Click the "Advanced" button
Select "Add External Folder" and choose the folder the "chapter31.Resources" .
ResourceBundle.getBundle() method is looking for the file in your classpath . if this file is not in your classpath it won't be able to find it.
The steps above adds the folder that "chapter31.Resources" to your classpath.
If this still does not work you can try passing the full path of the file to ResourceBundle.getResource().

can I load user packages into eclipse to run at start up and how?

I am new to java and to the eclipse IDE.
I am running Eclipse
Eclipse SDK
Version: 3.7.1
Build id: M20110909-1335
On a windows Vista machine.
I am trying to learn from the book Thinking in Java vol4.
The author uses his own packages to reduce typing. However the author did not use Eclipse and this is where the problem commes in..
This is an example of the code in the book.
import java.util.*;
import static net.mindview.util.print.*;
public class HelloWorld {
public static void main(String[] args) {
System.out.println("hello world");
print("this does not work");
}
this is the contents of print.Java
//: net/mindview/util/Print.java
// Print methods that can be used without
// qualifiers, using Java SE5 static imports:
package net.mindview.util;
import java.io.*;
public class Print {
// Print with a newline:
public static void print(Object obj) {
System.out.println(obj);
}
// Print a newline by itself:
public static void print() {
System.out.println();
}
// Print with no line break:
public static void printnb(Object obj) {
System.out.print(obj);
}
// The new Java SE5 printf() (from C):
public static PrintStream
printf(String format, Object... args) {
return System.out.printf(format, args);
}
} ///:~
The error I get the most is in the statement.
Import static net.mindview.util.print.*;
On this staement the Eclipse IDE says it cannot resolve net
also on the
print("this does not work");
The Eclipse IDE says that the class print() does not exist for the class HelloWorld.
I have been trying to get these to work, but with only limited success, The autor uses another 32 of these packages through the rest of the book.
I have tried to add the directory to the classpath, but that seems to only work if you are using the JDK compiler. I have tried to add them as libraries and i have tried importing them into a package in a source file in the project. I have tried a few other things but cant remember them all now.
I have been able to make one of the files work, the print.java file I gave the listing for in this message. I did that by creating a new source folder then making a new package in that foldeer then importing the print.java file into the package.
But the next time I try the same thing it does not work for me.
What I need is a way to have eclipse load all these .java files at start up so when I need them for the exercises in the book they will be there and work for me, or just an easy way to make them work everytime.
I know I am not the only one that has had this problem I have seen other questions about it on google searches and they were also asking about the Thinking In Java book.
I have searched this site and others and am just not having any luck.
Any help with this or sugestions are welcome and very appreciated.
thank you
Ok I have tried to get this working as you said, I have started a new project and I removed the static from the import statement, I then created a new source folder, then I created a new package in the source folder. Then I imported the file system and selected the the net.mindview.util folder.
Now the immport statement no longer gives me an error. But the the print statement does, the only way to make the print statement work is to use its fully qualified name. Here is the code.
import net.mindview.util.*;
public class Hello2 {
public static void main(String[] args) {
Hello2 test = new Hello2();
System.out.println();
print("this dooes not work");
net.mindview.util.Print.print("this stinks");
}
}
The Error on the print statement is:
The method print(String) is undefined for the type Hello2
and if I try to run it the error I get is:
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
The method print(String) is undefined for the type Hello2
at Hello2.main(Hello2.java:6)
The Statement::::: net.mindview.util.Print.print("this stinks") is the fully qualified print statement and it does not throw an error but it does totally defeat the purpose of the print.java file..
If you have any questions please ask Ill get back to you as soon as I can.

I've had similar issues. I solved it by following the steps below:
Click File->New->Java Project. Fill in UtilBuild for the ProjectName. Chose the option "Use project folder as root and click 'Finish'.
Right-click on UtilBuild in the PackageExplorer window and click New->package. For the Package Name, fill in net.mindview.util
Navigate within the unzipped Thinking In Java (TIJ) folder to TIJ->net\mindview\util. Here you will find all the source code (.java) files for util.
Select all the files in the net\mindview\util folder and drag them to the net.mindview.util package under UtilBuild in Eclipse. Chose the 'Copy Files' option and hit 'OK'.
You will probably already have the 'Build Automatically' option checked. If not, go to Project and click 'Build Automatically'. This will create the .class files from the .java source files.
In Eclipse, right-click on the project you were working on (the one where you couldn't get that blasted print() method to work!) Click Properties and Java Build Path->Libraries. Click 'Add Class Folder...' check the box for UtilBuild (the default location for the .class files).
I think the confusion here arises due to CLASSPATH. If you use Eclipse to build and run your code then Eclipse manages your CLASSPATH. (You don't have to manually edit CLASSPATH in the 'Environment Variables' part of your computer properties, and doing so changes nothing as far as Eclipse Build and Run are concerned.)
In order to call code that exists outside your current project (I will name this 'outside code' for convenience) you need to satisfy three things:
A. You need to have the .class files for that code (as .class files or inside a JAR)
B. You need to indicate in your source code where to look for the 'outside code'
C. You need to indicate where to start looking for the 'outside code'
In order to satisfy these requirements, in this example we:
A. Build the project UtilBuild which creates the .class files we need.
B. Add the statement import static net.mindview.util.Print.*; in our code
C. Add the Class Folder library in Eclipse (Java Build Path->Libraries).
You can investigate the effect of Step C by examining the .classpath file that lives directly in your project folder. If you open it in notepad you will see a line similar to the following:
<classpathentry kind="lib" path="/UtilBuild>
You should combine this with your import statement to understand where the compiler will look for the .class file. Combining path="/UtilBuild" and import static net.mindview.util.Print.*; tells us that the compiler will look for the class file in:
UtilBuild/net/mindview/util
and that it will take every class that we built from the Print.java file (Print.*).
NOTE:
There is no problem with the keyword static in the statement
import static net.mindview.util.Print.*;
static here just means that you don't have to give specify the class name from Print.java, just the methods that you want to call. If we omit the keyword static from the import statement, then we would need to qualify that print() method with the class it belongs to:
import net.mindview.util.Print.*;
//...
Print.print("Hello");
which is slightly more verbose than what is achieved with the static import.
OPINION:
I think most people new to Java will use Eclipse at least initially. The Thinking in Java book seems to assume you will do things via command line (hence it's guidance to edit environment variables in order to update CLASSPATH). This combined with using the util folder code from very early in the book I think is a source of confusion to new learners of the language. I would love to see all the source code organised into an Eclipse project and available for download. Short of that, it would be a nice touch to include the .class files in just the 'net/mindview/util' folder so that things would be a little easier.

U should import package static net.mindview.util not static net.mindview.util.Print
and you should extend the class Print to use its method.......

You should remove the static keyword from your import decleration, this: import static net.mindview.util.print.*; becomes this: import net.mindview.util.print.*;
If that also does not work, I am assuming you did the following:
Create your own project;
Start copying code directly from the book.
The problem seems to be that this: package net.mindview.util; must match your folder structure in your src folder. So, if your src folder you create a new package and name it net.mindview.util and in it you place your Print class, you should be able to get it working.
For future reference, you should always make sure that your package decleration, which is at the top of your Java class, matches the package in which it resides.
EDIT:
I have seen your edit, and the problem seems to have a simple solution. You declare a static method named print(). In java, static methods are accessed through the use of ClassName.methodName(). This: print("this dooes not work"); will not work because you do not have a method named print which takes a string argument in your Hello2 class. In java, when you write something of the sort methodName(arg1...), the JVM will look for methods with that signature (method name + parameters) in the class in which you are making the call and any other classes that your calling class might extend.
However, as you correctly noted, this will work net.mindview.util.Print.print("this stinks");. This is because you are accessing the static method in the proper way, meaning ClassName.methodName();.
So in short, to solve your problem, you need to either:
Create a method named print which takes a string argument in your Hello2 class;
Call your print method like so: Print.print("this stinks");
Either of these two solutions should work for you.

In my case I've dowloaded and decompressed the file TIJ4Example-master.zip. in eclipse workspace folder. The three packages : net.mindview.atunit, net.mindview.simple and net.mindview.util are in this point of the project :
and java programs runs with no problems (on the right an example of /TIJ4Example/src/exercises/E07_CoinFlipping.java)

NetBeans is not debugging correctly after I copy sources

Dunno why this happens... Ok here is the situation: I have a nb project on my laptop. I have the same project on my desktop. I copy the sources (not the entire project) on the desktop, overwriting the desktop sources. Everything cleans and builds ok. Then I start the debugger. On the main class I can debug step by step. If it goes into an internal method here is what happens:
Listening on 37574
User program running
LineBreakpoint test.java : 45 successfully submitted.
Breakpoint hit at line 45 in class test by thread main.
Thread main stopped at test.java:45.
User program running
Not able to submit breakpoint LineBreakpoint baseControllerManager.java : 41, reason: No executable location available at line 41 in class baseClasses.JNW.baseControllerManager.
Invalid LineBreakpoint baseControllerManager.java : 41
Debugger stopped on uncompilable source code.
User program finished
As you can see until I'm in static method main it works (line 45) as I jump inside a non static method (that is an override) it comes out with that... I tried to:
clean and build = no effect
manually delete build and dist = no effect
What do you suggest?
For the sake of completeness I'm attaching the sources of the main class:
import baseClasses.JNW.baseAction;
import baseClasses.JNW.baseContResult;
import baseClasses.JNW.baseController;
import baseClasses.JNW.baseControllerManager;
public class test {
public static class starter extends baseController {
public static final String ACTION_START = "ACTION_START";
#Override
public baseContResult doAction(baseAction action) {
if (ACTION_START.equals(action.action)) {
manager.log("action start...");
return new baseContResult(RESULT_OK, baseContResult.resultType.RESULT_OK);
}
return super.doAction(action);
}
#Override
public void init() {
super.init();
}
}
public void startMe() {
baseControllerManager manager;
try {
manager = new baseControllerManager();
} catch (Exception e) {
e.printStackTrace();
return;
}
starter st = new starter();
manager.setMainController(st);
manager.doAction(new baseAction(starter.ACTION_START));
}
public static void main(String args[]) {
test te = new test();
te.startMe();
}
}

Look in the file nbproject/project.properties for the property javac.debug and make sure that it's "true". If it is, grep for that property elsewhere in the nbproject directory and any local ant settings.
On a semi-related note: when I'm creating a project in NetBeans, even if the sources already exist elsewhere, I always create a new "Java Application", and let it populate the project directory as it wants. Then I can move in my sources and update the project, and NetBeans stays happy.
Edit after you tried setting javac.debug:
Looking at your question again, I see that you were able to set a breakpoint on test.java, but not able to set one on baseControllerManager.java. That indicates to me that you're getting the latter class from a JAR somewhere, not from your project directory.
So the first step is to make sure that you haven't defined a CLASSPATH environment variable. This is never a good thing to do, regardless of whether you're using an IDE or a manual build.
Next step is to look at the libraries that you've specified for the NetBeans project. You can use grep on a JARfile; the file directory is in plaintext. It should be sufficient to look for the unqualified classname.
And the final thing is to verify that you are indeed compiling the class, by looking for it in the build directory.

Generally, an uncompilable error means a symbol could not be resolved.
If you have dependencies on other projects, libraries, or jars, make sure they have built successfully / are present.
Checking "Build Projects on Classpath" (in project properties > Build > Compiling) will often fix this. If you don't have this checked, you are responsible for ensuring dependencies are already built.

The property was not present in project.properties. So I added it (at a point where there where many javac.* properties...). Then I grepped like this:
dario#dario-desktop:~/Scrivania/JNW$ grep -r javac.debug *
nbproject/project.properties:javac.debug=true
nbproject/build-impl.xml: <property name="javac.debug" value="true"/>
nbproject/build-impl.xml: <attribute default="${javac.debug}" name="debug"/>
nbproject/build-impl.xml: <javac debug="#{debug}" deprecation="${javac.deprecation}" destdir="#{destdir}" encoding="${source.encoding}" excludes="#{excludes}" fork="${javac.fork}" includeantruntime="false" includes="#{includes}" source="${javac.source}" sourcepath="#{sourcepath}" srcdir="#{srcdir}" target="${javac.target}" tempdir="${java.io.tmpdir}">
nbproject/private/private.properties:javac.debug=true
nbproject/project.properties~:javac.debug=true
In fact it sees my addition on the last line.
I cleaned and rebuilt the project. The debugger is not working again........... I think I'll kick my boss ass until he agrees to use eclipse or he fires me. I'll be unemployed but happy. Apart from joking, #kdgrgory, do you have any more ideas???

I had the same problem and found that if I run clean from project tab it solves the problem.