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Google OR-Tools in Intellij: UnsatisfiedLinkError

I am setting up a java framework that should use the Google OR-Tools. The code below compiles successfully, but throws an exception at runtime:
Exception in thread "main" java.lang.UnsatisfiedLinkError: com.google.ortools.linearsolver.operations_research_linear_solverJNI.MPSolver_CLP_LINEAR_PROGRAMMING_get()I
at com.google.ortools.linearsolver.operations_research_linear_solverJNI.MPSolver_CLP_LINEAR_PROGRAMMING_get(Native Method)
at com.google.ortools.linearsolver.MPSolver$OptimizationProblemType.<clinit>(MPSolver.java:221)
at Main.main(Main.java:15)
I am using Intellij 2018.3 on Windows 10. I spent a lot of time trying to get this run, but unsuccessful. Based on what I found on the internet, the exception might be caused by poor linking and/or missing external libraries on which OR-Tools depends. However, I don't have the background to resolve this issue, and also Intellij does not highlight anything. Any idea what the problem is?
For completion, this is the code I run:
import com.google.ortools.linearsolver.MPObjective;
import com.google.ortools.linearsolver.MPSolver;
import com.google.ortools.linearsolver.MPVariable;
public final class Main {
public static void main(String[] args) {
// Create the linear solver with the GLOP backend.
MPSolver solver =
new MPSolver("SimpleLpProgram", MPSolver.OptimizationProblemType.GLOP_LINEAR_PROGRAMMING);
// Create the variables x and y.
MPVariable x = solver.makeNumVar(0.0, 1.0, "x");
MPVariable y = solver.makeNumVar(0.0, 2.0, "y");
System.out.println("Number of variables = " + solver.numVariables());
// Create a linear constraint, 0 <= x + y <= 2.
MPConstraint ct = solver.makeConstraint(0.0, 2.0, "ct");
ct.setCoefficient(x, 1);
ct.setCoefficient(y, 1);
System.out.println("Number of constraints = " + solver.numConstraints());
// Create the objective function, 3 * x + y.
MPObjective objective = solver.objective();
objective.setCoefficient(x, 3);
objective.setCoefficient(y, 1);
objective.setMaximization();
solver.solve();
System.out.println("Solution:");
System.out.println("Objective value = " + objective.value());
System.out.println("x = " + x.solutionValue());
System.out.println("y = " + y.solutionValue());
}
}

In my case solution was simple - I just needed to add this singe line of code:
Loader.loadNativeLibraries();
where loader comes from com.google.ortools.Loader

Disclaimer: more a long comment than an answer...
note: I supposed you are using the github repository of or-tools if you used the binary package it should be more or less the same...
1) You must load the jni library which will load the OR-Tools C++ libraries and its dependencies...
/** Simple linear programming example.*/
public class Main {
static {
System.loadLibrary("jniortools");
}
public static void main(String[] args) throws Exception {
2) Did you manage to run the java samples ?
make run SOURCE=ortools/linear_solver/samples/SimpleLpProgram.java
ref: https://developers.google.com/optimization/introduction/java#simple_example
3) As Kayaman pointed out, you must pass the folder where the java runtime can find the native libraries (i.e. the JNI wrapper jniortools.dll and its dependencies libortools.dll)
if you look at the console log you'll see the full command line:
java -Xss2048k -Djava.library.path=lib -cp lib\sample.jar;lib\com.google.ortools.jar;lib\protobuf.jar ...\sample
Which comes from, the makefiles/Makefile.java file:
JAVAFLAGS = -Djava.library.path=$(LIB_DIR)
...
ifeq ($(SOURCE_SUFFIX),.java) # Those rules will be used if SOURCE contain a .java file
$(CLASS_DIR)/$(SOURCE_NAME): $(SOURCE) $(JAVA_OR_TOOLS_LIBS) | $(CLASS_DIR)
-$(DELREC) $(CLASS_DIR)$S$(SOURCE_NAME)
-$(MKDIR_P) $(CLASS_DIR)$S$(SOURCE_NAME)
"$(JAVAC_BIN)" -d $(CLASS_DIR)$S$(SOURCE_NAME) \
-cp $(LIB_DIR)$Scom.google.ortools.jar$(CPSEP)$(LIB_DIR)$Sprotobuf.jar \
$(SOURCE_PATH)
...
.PHONY: run # Run a Java program.
run: build
"$(JAVA_BIN)" -Xss2048k $(JAVAFLAGS) \
-cp $(LIB_DIR)$S$(SOURCE_NAME)$J$(CPSEP)$(LIB_DIR)$Scom.google.ortools.jar$(CPSEP)$(LIB_DIR)$Sprotobuf.jar \
$(SOURCE_NAME) $(ARGS)
endif
src: https://github.com/google/or-tools/blob/46173008fdb15dae1dca0e8fa42a21ed6190b6e4/makefiles/Makefile.java.mk#L15
and
https://github.com/google/or-tools/blob/46173008fdb15dae1dca0e8fa42a21ed6190b6e4/makefiles/Makefile.java.mk#L328-L333
note: you can run make detect_java to know the flags i.e. value of LIB_DIR
note: if you did use the precompiled package the Makefile is here:
https://github.com/google/or-tools/blob/stable/tools/Makefile.cc.java.dotnet
Then after you can try to add this option in Intellij...
You must understand that or-tools is a set of C++ native libraries which are wrapped to Java using the SWIG generator.

To make it work using Intellij (over a windows machine) you need to:
Install Microsoft Visual C++ Redistributable for Visual Studio
Download and extract the OR-Tools library for Java
In intellij, add jar dependency to the 2 jars under the lib folder of the extracted files (each of the 2 jars separately, do not add to lib folder itself. This is why).
Add the lib library path to VM options. In Intellij edit your run-configuration and add to vm options: -Djava.library.path=<path to the lib folder that hold the jars>
Load the jni library statically by adding the below code to your class (as mentioned here.)
static {
System.loadLibrary("jniortools");
}

Missing resolveStrategy breaks DSL when executed from runnable jar

I'm using the Groovy Spreadsheet Builder within one of my Grails projects to export some data as Excel file.
Everything works great until I create a runnable jar (using gradle assemble) and use this.
I'm using the builder within a service like this:
class ExcelService {
...
void export(OutputStream outputStream) {
...
PoiSpreadsheetBuilder.create(outputStream).build {
apply ExcelStylesheet
...
}
}
...
}
When I try to export my data from the app started using the generated jar I will get the following MissingMethodException:
groovy.lang.MissingMethodException: No signature of method: my.package.ExcelService.apply() is applicable for argument types: (java.lang.Class)
The (Java) interface of SpreadsheetBuilder looks like this:
public interface SpreadsheetBuilder {
void build(#DelegatesTo(strategy = Closure.DELEGATE_FIRST, value = WorkbookDefinition.class) #ClosureParams(value = FromString.class, options = "builders.dsl.spreadsheet.builder.api.WorkbookDefinition") Configurer<WorkbookDefinition> workbookDefinition);
}
While debugging the execution of the code and the jar I found the difference while stepping through invokeMethod() of ClosureMetaClass.
When closure.getResolveStrategy(); in the working version is called Closure.DELEGATE_FIRST will be returned. Debugging the jar, the result will be 0 so that the MissingMethodException will be thrown later due to the wrong resolve strategy.
For now I have no idea how to solve this problem.
What is/could be the reason for this behavior?
What can I do to solve this issue?
I'm using Grails 3.3.8 with Java OpenJDK 1.8.0_192.

If you don't need to support JDK 7, you could upgrade to Groovy Spreadsheet Builder 2.0.0.RC1 which is only JDK 8 compatible but appears to solve the problem.

#ClosureParams and #DelegatesTo are applicable to parameters of type groovy.lang.Closure. In this case, you have applied it to Configurer<WorkbookDefinition>.

CXF - Cannot Add Feature

I have been using Apache CXF 2.7.0 for quite a while now, but recently I had to restructure my project in Eclipse. After I did that, for some reason, I cannot add a "WSAddressingFeature" Feature to the endpoint.
What am I missing??
endpoint.getFeatures().add(new org.apache.cxf.ws.addressing.WSAddressingFeature());
Eclipse is reporting that:
"The method add(Feature) in the type List<Feature> is not applicable for the arguments (WSAddressingFeature)"
This is my full implementation:
String url = "http://localhost:" + m_Port + "/infoburst/handler";
Object implementor = new HandlerImpl();
org.apache.cxf.jaxws.EndpointImpl endpoint = new org.apache.cxf.jaxws.EndpointImpl(implementor);
endpoint.getFeatures().add(new org.apache.cxf.ws.addressing.WSAddressingFeature());
endpoint.publish(url);
org.apache.cxf.endpoint.Server server = endpoint.getServer();
org.apache.cxf.jaxws.JaxWsServerFactoryBean serverFB = endpoint.getServerFactory();
If I remove the line of code that adds the feature, the following error occurs:
Exception in thread "main" java.lang.NoSuchMethodError: org.apache.cxf.common.util.ReflectionUtil.getDeclaredMethod(Ljava/lang/Class;Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Method;
at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.bindOperation(JaxWsServiceFactoryBean.java:276)
at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.createOperation(ReflectionServiceFactoryBean.java:1045)
at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.createOperation(JaxWsServiceFactoryBean.java:642)
at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.createInterface(ReflectionServiceFactoryBean.java:990)
at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.buildServiceFromClass(ReflectionServiceFactoryBean.java:481)
at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.buildServiceFromClass(JaxWsServiceFactoryBean.java:704)
at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.initializeServiceModel(ReflectionServiceFactoryBean.java:550)
at org.apache.cxf.service.factory.ReflectionServiceFactoryBean.create(ReflectionServiceFactoryBean.java:265)
at org.apache.cxf.jaxws.support.JaxWsServiceFactoryBean.create(JaxWsServiceFactoryBean.java:215)
at org.apache.cxf.frontend.AbstractWSDLBasedEndpointFactory.createEndpoint(AbstractWSDLBasedEndpointFactory.java:102)
at org.apache.cxf.frontend.ServerFactoryBean.create(ServerFactoryBean.java:159)
at org.apache.cxf.jaxws.JaxWsServerFactoryBean.create(JaxWsServerFactoryBean.java:211)
at org.apache.cxf.jaxws.EndpointImpl.getServer(EndpointImpl.java:456)
at org.apache.cxf.jaxws.EndpointImpl.doPublish(EndpointImpl.java:334)
at org.apache.cxf.jaxws.EndpointImpl.publish(EndpointImpl.java:251)
at org.apache.cxf.jaxws.spi.ProviderImpl.createAndPublishEndpoint(ProviderImpl.java:155)
at javax.xml.ws.Endpoint.publish(Unknown Source)
at com.infosol.infoburst.XI4Service.HandlerService.publish(HandlerService.java:106)
at com.infosol.infoburst.XI4Service.HandlerService.main(HandlerService.java:42)

This is why I really don't enjoy working in the Java environment...
To fix the ""The method add(Feature) in the type List is not applicable for the arguments (WSAddressingFeature)" error:
Go into "Configure Build Path"
Go to "Order and Export"
Move the "cfx-2.7.0.jar" file to a higher priority, this may take a little trial and error.
Once the CFX file is moved up in priority, the error will go away.

How to load AttachProvider (attach.dll) dynamically

I'm using com.sun.tools.attach from jdk's tools.jar and it need an specified java.library.path env pointing to attach.dll at startup to properly instatiate provider such as WindowsAttachProvider. For some reasons I need to dynamic loading one of bundled attach.dll. I'm try to use some like this:
public static void main(String[] args) throws Exception {
Path bin = Paths.get(System.getProperty("user.dir"),"bin").toAbsolutePath();
switch (System.getProperty("os.arch")) {
case "amd64":
bin = bin.resolve("win64");
break;
default:
bin = bin.resolve("win32");
}
// Dynamic setting of java.library.path only seems not sufficient
System.setProperty("java.library.path", System.getProperty("java.library.path") + File.pathSeparator + bin.toString());
// So I try to manual loading attach.dll. This is not sufficient too.
System.load(bin.resolve("attach.dll").toString());
// I'm using com.sun.tools.attach in my app
new myApp();
}
If I run this out of jdk (in normall jre) it's report to me:
java.util.ServiceConfigurationError: com.sun.tools.attach.spi.AttachProvider:
Provider sun.tools.attach.WindowsAttachProvider could not be instantiated:
java.lang.UnsatisfiedLinkError: no attach in java.library.path
Exception in thread "main" com.sun.tools.attach.AttachNotSupportedException:
no providers installed
at com.sun.tools.attach.VirtualMachine.attach(...
How to install attach provider without specifying -Djava.library.path to point attach.dll at startup?

The API you are using is using loadLibrary(String). It seems you cannot successfully pre-empt (cause it to succeed) this by invoking the more explicit load(String) first.
So you must to specify the path in java.library.path.
That System property is set once early in JVM lifecycle and is not modifiable by standard means.
So the conventional solution will be to pass an appropriate java.library.path when you launch the JVM.
Alternatively, you could look into the hacks to change this property after JVM startup using reflection. I have not tried any of these.
For example, see here:
System.setProperty( "java.library.path", "/path/to/libs" );
Field fieldSysPath = ClassLoader.class.getDeclaredField( "sys_paths" );
fieldSysPath.setAccessible( true );
fieldSysPath.set( null, null );
BTW, I would recommend pre-pending your custom path to the existing path, rather than replacing it.

Problems using Matlab Builder JA

First of all I would like to thank in advance everyone for reading such a long post. I really appreciate your help.
The thing is that I've been doing some research on how to "connect" Matlab and Java for a project I am working on for university. I figured that the most suitable option was using Matlab Builder JA, but I'm having a lot of troubles with it.
I follow step by step the instructions described on a tutorial (the link of the video in below) but get compilation errors over and over, and I really don't know how to fix them. The tutorial is about creating a Java package (demo.jar) with MATLAB ("com.demo"), which contains a class (MLTestClass) with a function makeSqr(n) which returns an n × n square matrix. Then I go to Eclipse, I add to the project both libraries javabuilder.jar and demo.jar and then create the following class:
public class Driver {
public static void main (String[] args) {
MLTestClass x = null;
Object result [] = null;
try {
x = new MLTestClass ();
result = x.makeSqr (1, 5);
System.out.println (result [0]);
} catch (MWException e) {
e.printStackTrace();
}
}
}
Of course I import com.demo.* and com.mathworks.toolbox.javabuilder.*.
Here are the errors the console gives me:
Exception in thread "main" java.lang.ExceptionInInitializerError
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration.getProxyLibraryDir(MCRConfiguration.java:163)
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration$MCRRoot.get(MCRConfiguration.java:77)
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration$MCRRoot.<clinit>(MCRConfiguration.java:87)
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration.getMCRRoot(MCRConfiguration.java:92)
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration$ModuleDir.<clinit>(MCRConfiguration.java:66)
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration.getModuleDir(MCRConfiguration.java:71)
at com.mathworks.toolbox.javabuilder.internal.MWMCR.<clinit>(MWMCR.java:1573)
at com.demo.DemoMCRFactory.(DemoMCRFactory.java:122)
at com.demo.MLTestClass.(MLTestClass.java:63)
at Driver.main(Driver.java:12)
Caused by: java.lang.NullPointerException
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration$ProxyLibraryDir.get(MCRConfiguration.java:143)
at com.mathworks.toolbox.javabuilder.internal.MCRConfiguration$ProxyLibraryDir.<clinit>(MCRConfiguration.java:158)
... 10 more
Just in case, link tutorial (it's the video): http://www.mathworks.nl/products/javabuilder/description2.html
Anyone has any ideas what the problem could be? It says something about NullPointerException, but I don't know how to solve it as the constructor is provided by the class created with MATLAB. I didn't have any issues installing MCR, and by the way I have MacOS, which I hope is not the source of the problem :).
Again, sorry for the long post and thank you for your time.
Béntor.

Yes, please install MCR. The installation also mentions about setting environmental variables like LD_LIBRARY_PATH etc. If you are using eclipse, i would recommend you update the environmental variables
right click->
properties ->
run/debug settings->
environmental variables
I also had to make sure that variable MCR_CACHE_ROOT pointed to different directory since my home directory was not big enough.

You have install MCR (avaliable in http://www.mathworks.com/products/compiler/mcr/index.html)

None of the above solutions helped me (I already had MCR installed and Macs use DYLD_LIBRARY_PATH instead of LD_LIBRARY_PATH), and noone else online seemed to know. Finally in desperation, I tried editing the DYLD_LIBRARY_PATH and finally got it to work by removing the last part of it: /Applications/MATLAB/MATLAB_Compiler_Runtime/v82/sys/java/jre/maci64/jre/lib
Now the demo application from the tutorial works.
Next comes trying to make my code work.

OS X Paths for Run-Time Deployment
Use these setenv commands to set your MATLAB Runtime paths.
setenv DYLD_LIBRARY_PATH \
mcr_root/version/runtime/maci64 \
mcr_root/version/bin/maci64 \
mcr_root/version/sys/os/maci64
Source: http://www.mathworks.com/help/compiler_sdk/java/mcr-path-settings-for-run-time-deployment.html