Develop Reference

Jpype import cannot find module in jar

I have received the task, at work, to find a way to use some methods from an existent jar file in a Python project. I have very limited experience in Python, but I have worked with that specific jar file before (it is part of a project we are working on). I am not allowed to modify much of both projects, and they are required to be as independent as possible.
I have researched multiple ways to include the jar methods in Python. So far, I have tried Jython (which I cannot use because the Python project uses PyQt among other libraries, which force the use of CPython, if my understanding is correct), Pyjnius and JPype. JPype seems the most promising, but I cannot get it working either. I have pasted the my code below, slightly censored because I don't know how much I am allowed to share.
from jpype import *
import jpype.imports
try:
jpype.addClassPath("jars/sdk.jar") #the relative path to the jar file
jpype.startJVM(convertStrings=False)
java.lang.System.out.println(jpype.getClassPath()) #printing the classpath to check, the path is correctly pointing to the sdk.jar file
java.lang.System.out.println("Hello world") #just to check if jpype is installed correctly, works
jpype.imports.registerDomain("a")
from a.b.c.d.e.f.g.h import SomeClass #fails here
except OSError as err:
print(err) # ToDo: Remove print when done
pass
The error I am getting is that the module a.b.c.d.e.f.g.h.SomeClass could not be found. I have tried different ways to give the path (absolute path, relative path, place the jar in different places in the project and outside of it), but that doesn't seem to be the problem, as the path printed is the correct absolute path to the jar file.
Also, the jar is used in other (Java) projects and it works. It is created using maven package (using IntelliJ, if it is relevant, and the same Java version as the one used by the JPype JVM). In the Java projects, the import would be:
import a.b.c.d.e.f.g.h.SomeClass;
I have copied this and just transformed the syntax into Python.
I have also tried to create the class with JObject (which I probably didn't do right anyway) and also tried the older syntax (to my understanding) with JPackage. For the JPackage way, I am getting the exception that the package a.b.c.d.e.f.g.h.SomeClass.someMethod is not Callable, which to my understanding is an equivalent exception to the one I'm getting using jpype imports. I have already gone through all the questions I could find here with similar problems, but none of those solutions have helped me.
Can anyone suggest some possible solution? Or can anyone see what I'm doing wrong? Suggestions of other possibilities to replace JPype are also welcomed. If there is any clarification needed, I will edit the question.

The only thing that seems likely if the jar is on the classpath and failed to import would be for there to be some missing dependency. You have two other ways to try loading the class which may provide additional diagnostics.
jpype.JClass("a.b.c.d.e.f.g.h.SomeClass")
and
jpype.JClass("java.lang.Class").forName("a.b.c.d.e.f.g.h.SomeClass")
The first is manually loading a class by full class specification. It is mechanically what is happening under the import. The second is calling for Java to load the class (bypassing all of JPype). It returns a java.lang.Class which can be passed to JClass to make a wrapper.
Common failures include missing a jar or native library, attempting to start JPype from within a module and having the wrong relative path, error in initialization of the class due to missing resource. JPype is just calling JNI calls, so if everything is fine on Java end it should work. Given that you checked the java.class.path System variable, it has to be something to do with class resources.
The JPype user manual has an alternatives section if you would like to try to find another package. Most of the alternatives with the exception of PyJnius appear to be unmaintained.

Failing to obfuscate Java code with ProGuard

I'm trying to optimize / obfuscate a java project with ProGuard.
I extract the project as a runnable jar from eclipse, and it runs just fine.
When I try to compress it with ProGuard, I get thousands of warning and errors, in particular at the end:
Note: there were 1 classes trying to access generic signatures using reflection.
You should consider keeping the signature attributes
(using '-keepattributes Signature').
Note: there were 14 unresolved dynamic references to classes or interfaces.
You should check if you need to specify additional program jars.
Note: there were 2 class casts of dynamically created class instances.
You might consider explicitly keeping the mentioned classes and/or
their implementations (using '-keep').
Note: there were 15 accesses to class members by means of introspection.
You should consider explicitly keeping the mentioned class members
(using '-keep' or '-keepclassmembers').
Warning: there were 13229 unresolved references to classes or interfaces.
You may need to add missing library jars or update their versions.
If your code works fine without the missing classes, you can suppress
the warnings with '-dontwarn' options.
Warning: there were 61 instances of library classes depending on program classes.
You must avoid such dependencies, since the program classes will
be processed, while the library classes will remain unchanged.
Warning: there were 18 unresolved references to program class members.
Your input classes appear to be inconsistent.
You may need to recompile the code.
The external libs I used in the project are added to the jar upon exporting it from eclipse. ("Extract required libraries into jar"). I did not use the "repack into jar" option because it really slows jars down.
The libs in particular are:
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
Am I doing something fondamentally wrong here?
I have tried without success the suggestions of proguard, and my code compiles in eclipse with no warnings.
It's a very big project so I can't really provide an MCVE, but if someone could point me in the right direction here as to what I'm missing, I'd really appreciate it.
Example of the warning: (It goes on for every single method)
http://pastebin.com/m9hX9LJA
Obviously this might be too general of a problem for you guys to fix, however I might be doing some major obvious mistake that I'm not realizing, that's what I'm going for with this.

Notes are just suggestions, but warnings point out inconsistencies in the input. Notably, the 13229 unresolved references suggest that you are providing the main code of your application (with -injars), but not its libraries (with -injars or -libraryjars). I don't know of Eclipse's Extract or Repack options, but you should check the contents of your input jar(s).
See the ProGuard manual > Troubleshooting > Warning: can't find referenced class.

Running Java class with JMeter (Bean Shell)

I have written a Java Class for use in JMeter, packaged the project as a .jar file and moved that file into the lib/ext folder in the jmeter directory. I have seen documentation on how to proceed but they give contradictory answers.
The first way is to use the BeanShell Sampler to import my package and class, create an object of the class and run the methods that way. I have used this method using example classes with more simple file structures than that of class I want to run. The example classes work with the following BeanShell script.
import tools.JmeterTools;
JmeterTools jt = new JmeterTools();
jt.foo();
When I try to use this method for the class I want to run, it states that the variable declaration is an error and the Class cannot be found. I assume this is because I do not understand what to import exactly, as the file structure in my project is a little odd.
The second uses the BeanShell PreProcessor to add the jar to the class path. This method I have not been able to get to work at all, but have read many accounts of others finding success. It works as follows:
addClassPath("directory path to jar\lib\ext\foo.jar");
JMeterTest jtm = new JMeterTest();
jmt.test();
Would anyone have any knowledge of which way would work better or any ideas on how to fix the import?
The import I have been using in the BeanShell script is the following:
import client.JMeterTest;
The package line at the top of my class is the following
import com.x.foo.client;

You need to have your jar file in JMETER_HOME/lib folder.
lib/ext is for JMeter extensions/plugins etc.
Once you have placed your jar, you might have to restart JMeter.

Running external classes from Beanshell should work fine given the following preconditions met
Your test with dependencies is located in JMeter classpath.
JMeter restart is required to pick new libraries up
You need to provide full package name plus full class name (or wildcard) for import.
Either
import com.x.foo.client.JMeterTest;
or
import com.x.foo.client.*;
And finally it is recommended to use JSR223 Sampler and use "groovy" as a language. Beanshell interpreter has severe performance issues so use it for something very "light" like variable amendment, converting variable to property, etc. For generating the real load use JSR223 and groovy as it implements Compilable interface and hence you can achieve performance similar to native Java code. See Beanshell vs JSR223 vs Java JMeter Scripting: The Performance-Off You've Been Waiting For! guide for detailed explanation, benchmarking and instructions on installation of groovy scripting engine support.

For anyone who has this issue in the future. The answers given by others are correct. It wasn't working for me because I had forgotten that Maven does not package files in the test directory when a jar is made.
This link may help if anyone ever does this in the future.
Generate test-jar along with jar file in test package

JAVA creating custom .class library file from several existing ones ECLIPSE

I was using JD-GUI to get readable content of the several .class files in order to create a custom one, because many parts of the original libraries are not used (save space and performance)
So I read the code and started creating an eclipse library project in eclipse pasting them in.
soon apeared the first weird errors:
The method getLogger(Class) from the type Logger refers to the missing type Class
Implicit super constructor Object() is undefined for default constructor. Must define an explicit constructor
and so on.
Does anyone has experience in creating libraries from other libraries in eclipse? what is going wrong?
thank you.
EDIT:
it seems that several imports are not found:
error example:
The import org.w3c.dom.stylesheets cannot be resolved
how can this be, when the original libraries are working fine? I did not remove a single class. my custom library is just a merged one with 100% the same content.

Java disutil CoordinateConversions import problems

I'm writing a Java class that will be used to send PDUs across a network- to do this, I am following the tutorial at: Tutorial
In the example, the line:
double lla[] = CoordinateConversions.xyzToLatLonDegrees(c);
appears towards the end of the class, and I see that CoordinateConversions has been imported with the line:
import edu.nps.moves.disutil.CoordinateConversions;
I have tried using the xyzToLatLonDegrees(); method in the class that I am writing- calling it in the same way as is done in the example. However, for some reason, I get a compile error that says:
CoordinateConversions cannot be resolved
on the line where I'm trying to use it, and
The import edu.nps.moves.disutil.CoordinateConversions cannot be resolved
on the line where I am importing it.
Does anyone know why this is, and how I can fix the import, so that I can use the xyzToLatLonDegrees() method?

You need to have the CoordinateConversions class on your classpath. Either by obtaining the source and dropping it into your project (possibly adjusting package names, and only if the license allows), or by finding a JAR containing that class and adding it to your build path in your IDE.
You probably need to download the Java files from here.