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ServiceLoader cannot find service loaded from path

I have been trying to do a kind of plugin-system using the ServiceLoader. There are 2 modules, the first provides the abstract class LoadedRealmPlugin. The second one extends this class. I have added the file corresponding to the full name of the ServiceProvider and added the service-class to it. IntelliJ does not find any errors (but when changing the filename or classname it does). Here is the structure:
MainModule
src
main
java
com.interestingcompany.mainmodule
LoadedRealmPlugin
MainModule.iml
Plugin
META-INF
services
com.interestingcompany.mainmodule (-> Content: "PluginExtension")
src
PluginExtension
Plugin.iml
(This is simplified, I left out classes that (I think) are not important to the ServiceLoader. I can post a screenshot of the actual structure if anyone needs it)
Here is the code I use to load the Service:
File file = new File("Plugins/Plugin.jar");
URLClassLoader c = new URLClassLoader(new URL[]{file.getAbsoluteFile().toURI().toURL()});
ServiceLoader<LoadedRealmPlugin> loader = ServiceLoader.load(LoadedRealmPlugin.class, c);
LoadedRealmPlugin p = loader.iterator().next(); // Throws a java.util.NoSuchElementException
p.Initialize(RealmPath); // Abstract method implemented in the service
return p;
When trying to run it, I always get an empty ServiceLoader. I looked at this post, but I was not quite sure about how to apply that answer since I am trying to load my plugin from a file. In addition, I found this post. Yet, there was no answer, just some comments that did not seem to have answered the question.
As you might have been able to tell, this is my first time working with classloaders. If there is any additional information needed, just ask me. Thank you for reading through my beginner troubles.

package-less classes are in the unnamed package, which is inaccessible to rather a lot of code, notably including here.
Put PluginExtension.java in a package, make sure the content of your META-INF/services/com.ic.mainmodule file reflects this (content should be pkg.PluginExtension), and it'll work fine.

New value added to Java Enum not available during debug

I am having the following problem:
I have an Enum that was originally declared with 5 elements.
public enum GraphFormat {
DOT,
GML,
PUML,
JSON,
NEO4J,
TEXT {
#Override
public String getFileExtension() {
return ".txt";
}
};
Now I need to add an additional element to it (NEO4J). When I run my code or try to debug it I am getting an exception because the value can't be found in the enum.
I am using IntelliJ as my IDE, and have cleaned the cache, force a rebuild, etc.. and nothing happens. When I look at the .class file created on my target folder, it also has the new element.
Any ideas on what could be causing this issue ?

I found my problem and want to share here what was causing it. My code was actually for a Maven plug-in which I was pointing to another project of mine to run it as a goal. However the pom.xml of my target test project was pointing to the original version of the plug-in instead of the one I am working on, and that version of course is outdated and does not include the new value. Thank you.

Using Java class in Matlab

I've been struggling with this problem for two days now and no resource I've found have been able to solve it.
I am trying to call a java class (added the link at the bottom) from Matlab (version 7.13.0.564 (R2011b)). I've compiled the java class using java 1.6 into a .class file and also added the path to the folder where the file is situated using javaaddpath (I've of course checked that the path is correct in the list of dynamic paths). However, when I try to call the class from Matlab using javaMethod('main','PerlinNoiseGenerator','') I get the error:
"No class PerlinNoiseGenerator can be located on Java class path"
I would be extremely grateful if someone with experience in calling java from Matlab could put together a short tut on how to do this. I am probably going to distribute my code so I kinda need to set the java path dynamically and from what I've read it really should be possible although I've seen post that indicate that it could be the cause of the problem.
http://svn.j3d.org/code/tags/Xj3D-M10/src/java/org/j3d/texture/procedural/PerlinNoiseGenerator.java

Usually I create jar files that contain java classes. I also had problems loading individual java classes before. In your case I did the following on xubuntu 13.04 x64 and Matlab 2013a x64 to load your particular class:
Compile it using java 6 (not the default 7) with option -d . to create a set of package folders, as your class defines a package org/j3d/texture/proecedural/ etc:
/usr/lib/jvm/java-6-openjdk-amd64/bin/javac -d . PerlinNoiseGenerator.java
This will compile the class and make in the current director (thus .) the set of package folders.
Make jar file containing your class again using jar from java 6. I named it javaNoise.jar:
/usr/lib/jvm/java-6-openjdk-amd64/bin/jar cf javaNoise.jar ./org/j3d/texture/procedural/PerlinNoiseGenerator.class
In Matlab, in the directory where javaNoise.jar is:
javaaddpath('./javaNoise.jar');
Create object of your java class:
png=org.j3d.texture.procedural.PerlinNoiseGenerator()
% results in: png = org.j3d.texture.procedural.PerlinNoiseGenerator#3982a033
To test it, I just generated some 1D noise:
png.noise1(1.2)
ans = -0.0960
Hope this helps.
P.S.
javaMethod('main','PerlinNoiseGenerator','') wont work because this class has no main method:-).

Your notation to the compiler of the constructor is a polymorphic class meaning "use appropriate constructor that is called at runtime".
public PerlinNoiseGenerator()
public PerlinNoiseGenerator(int seed)
The first form with no argument can be called but is irrelevent because the line with this(DEFAULT_SEED) attempts to call itself but only one constructor is allowed used
Second constructor has int for an argument but requires being loaded by an already loaded class.
Use the first version and change the case sensitive name of the one with the argument and remove this(DEFAULT_SEED) from it replace with the method name(the one you changed from a constructor that has the argument).
e.g. public perlinNoiseGenerator(int seed)
note: by convention java code method names start with a lower-case letter.
A final note, java arguments from the command line come in as "String" data type through the "main" method, a starter method for applications (gui or command prompt).
The first argument on the main method argument is the first commandline argument.
public static void main(String[] Args){
new PerlinNoiseGenerator(Args); // recursive class call
}//end main method
int[] args; // global
public PerlinNoiseGenerator(String[] Args){
int arglength=Args.length();
args = new int[arglength];
for(int cnt=0;cnt<arglength;cnt++){
Args[cnt].trim();
args[cnt]=new Integer(Args[cnt]).intValue();
}//enfor
perlinNoiseGenerator(args[0]); // call method
}//end constructor

Vim Syntastic Java Unaware of Current Project Classes

Using Vim Syntastic with an android project. (e.g. com.myproject.project) It's not aware of classes declared within my project but outside of the current file. e.g. the following flags errors:
import com.myproject.project.SomeClass;
...
SomeClass someclass = new SomeClass();

Saw this post Configure syntastic to work fine with Android projects which solve the problem:
Method 1:
Inside vim editor
:SyntasticJavacEditClasspath
Then add the following to the buffer window
/path-to-your-app/bin/classes
/path-to-your-android-sdk/platforms/android-19/*.jar
Method 2:
Add the following to the .vimrc:
let g:syntastic_java_javac_classpath = "/<path-to-your-app>/bin/classes:/<path-to-your-android-sdk>/platforms/android-19/*.jar"

Here is a summary of the various methods which worked for me in linux vim7.4 and Syntastic3.7.0-224 with credit to each.
Method 1 - manual creation of .syntastic_javac_config
1. Edit .vimrc and use this syntax:
let g:syntastic_java_javac_config_file_enabled = 1
2. Where you edit your vim files, add this to a file named .syntastic_javac_config
let g:syntastic_java_javac_classpath = '/home/davis/progs/princeton-algos/week1/libs/algs4.jar'
Method 2 - advantage no matter where you edit the class path is known.
1. Edit .vimrc and use this syntax:
let g:syntastic_java_javac_classpath = "/home/davis/progs/princeton-algos/week1/libs/algs4.jar"
This adds the jar and
Method 3 - Automatic generation of .syntastic_javac_config file
1. Edit .vimrc and use this syntax:
let g:syntastic_java_javac_config_file_enabled = 1
2. Edit a java file with vim
3. :SyntasticJavacEditClasspath
When the edit window opens, add the class path without quotes and a newline after each entry the class path. In my case, this is the entry
for the setting includes the current folder as well:
/home/davis/progs/princeton-algos/week1/libs/algs4.jar
.
4 :wq the edit setting window
5. Now the class path is set for syntastic when editing files from that location. If you edit from a new directory, you will need to repeat the process.
Besides the comments above, this post also helped.

Parsing java code and adding methods with AST (JDT Eclipse)

I have a .java file which contains a class. I want to add a method to that class but I can't find a real useful "HOWTO" or examples around.
I'm using Eclipse and its JDT plugin for AST.
I tried a code that creates an ICompilationUnit from a project
IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject("ProjName");
IJavaProject javaProject = JavaCore.create(project);
IPackageFragment package1 = javaProject.getPackageFragments()[0];
ICompilationUnit unit = package1.getCompilationUnits()[0];
then add a method with astrewrite.
But it seems to work only if I run all as a Plugin Project and not a simple Java Application.
I need to write an application in java that "simply" parse a java file and adds method to its class.
What I supposed to do is:
1) Create an ICompilationUnit directly form the .java file I want to parse (eventually located in my own project's directory)
2) Using another way
Both case I can't go further. Anyone can help me?

When you need to make a change by adding something to the compilation unit, you will have to use the functions provided by CompilationUnit to create new nodes.
To add a method to "unit" you will have to :
Create a MethodDeclaration node using your compilation unit :
MethodDeclaration md = unit.getAST().newMethodDeclaration();
Customize this method declaration to your requirements :
md.setName( unit.getAST().newSimpleName( "newMethod" ) );
md.setBody( unit.getAST().newBlock() );
this will produce : void newMethod() {}
Obtain the TypeBinding from "unit" :
TypeDeclaration typeDeclaration = ( TypeDeclaration )unit.types().get( 0 );
Add your newly created MethodDeclaration to the body declarations :
typeDeclaration.bodyDeclarations().add( md );
There's a method called getMethods() on TypeDeclaration but it doesn't return a live list of MethodDeclarations, therefore you can't modify that directly.

It's really easy to read the source file as text and replace the last } with the method declaration plus }. Obviously this doesn't work if someone puts multiple top-level classes in one file (which is extremely rare and I doubt you'll have a problem with that).