I am trying to develop an application using java opencv 3.0.0-beta using scala.
I am getting a runtime error:
java.lang.UnsatisfiedLinkError: java.lang.UnsatisfiedLinkError: org.opencv.imgcodecs.Imgcodecs.imread_1(Ljava/lang/String;)J
While researching the cause i have created the following simple application the exhibits similar behaviour:
import reflect._
import org.opencv.core.Core
import org.opencv.core.Mat
import org.opencv.core.CvType
import org.opencv.imgcodecs.Imgcodecs
object main extends Application {
System.loadLibrary(Core.NATIVE_LIBRARY_NAME)
val what = "something.png"
val mat = Imgcodecs.imread(what)
Imgcodecs.imwrite("something_else.png", mat)
}
The major difference is that, if run as "sbt run" it performs as expected. if the appropriate lines are removed from the above the code fails in REPL.
I suspect that this issue is related to the original issue, but have no proof.
If i look at the memory map of the JVM in both cases i have the expected libs loaded.
If the code is inspected i find no definition of org.opencv.imgcodecs.Imgcodecs.imread_1
I am quite lost as to where to go next in diagnosing this issue.
Is there anyone who has come across this issue?
Thanks
i haven't used openCV3.0 yet, as it has major changes and breaks opencv 2.4.x code , are you supplying the library path to
sbt run
add
javaOptions in run += "-Djava.library.path=lib/opencv/"
to your build.sbt file or pass on cmd line
sbt run -Djava.library.path=lib/opencv/
opencv folder should have your files that gets generated along with your jar file
i have java bindins for 2.4.9 , 2.4.10 and 3.0.0 for java 7 and 8 in this git repo if you need them
git#gitlab.com:opencv/java_lib.git
Related
After switching to Java 11, sbt tests started to fail with the exception "No configuration setting found for key 'akka'". We are using sbt assembly plugin on the project but since the tests are run not inside jar but using sbt <module_name>/test, looks like there are some issues with building test resources/paths.
List of things I did:
Added concat MergeStrategy for 'reference.conf' file. Jar that is assembled has all files inside and there are no issues with that, so it is only a test step issue.
Checked class path for tests using 'export <module_name>/test:fullClasspath' in sbt before and after migrating to Java 11. They are the same.
Everything else except of a test where I create actor system works good.
Code that creates actor system:
object MyObjectTest extends AsyncFunSuite {
private implicit val system: ActorSystem = ActorSystem("MyActorSystem")
private implicit val ex: ExecutionContext = system.dispatcher
}
At the moment I do not have any ideas what should I check next, so any suggestions would be appreciated.
P.S. running tests inside IDEA works good, but we have CI/CD job that runs tests using sbt test command.
I guess there are some issues when you are using sbt + Java 11. I tried to reproduce this error using a small project with the same configuration but was not been able to do it. However, the issue was fixed using the following option in sbt:
Test / fork := true
According to sbt documentation, this property creates a separate JVM for running all tests. I think all configurations have been set up correctly for another JVM.
Hope this answer will help someone in future.
This question already has answers here:
How to run jar generated by package (possibly with other jars under lib)?
(3 answers)
Closed 2 years ago.
after packaging and executing a Scala application (build.sbt with version 2.12.0, but in fact having 2.13.3 installed) with SBT (version 1.3.13), I get the following error:
Exception in thread "main" java.lang.NoSuchMethodError: scala.Predef$.wrapRefArray([Ljava/lang/Object;)Lscala/collection/mutable/WrappedArray;
at org.example.GreetWorld$.printMessage(GreetWorld.scala:5)
The source file GreetWorld.scala that caused the error looks like this:
package org.example
object GreetWorld {
def printMessage(theMessage:String):Unit = {
println(s"${theMessage} from me")
}
}
The main file that is invoking the file above looks like this:
package org.example
object HelloWorld {
def main(args: Array[String]) = {
GreetWorld.printMessage("Hello")
}
}
Does anybody know the root cause? At first I thought it has to do with the SBT shell picking Java 11, but even after changing my Windows' JAVA_HOME to Java 8, I still get the same error. Compiling and running it in SBT Shell works fine. Only the JAR execution fails.
The error is pretty simple. When you run package you create a JAR which only contains the classes corresponding to your source code, nothing more. And your code depends on the Scala stdlib, so if you try to run it with java - jar it will fail with a class path error.
You have 4 solutions:
Run the JAR using scala directly. However, you need to use the same major version it was used to compile.
Put the Scala library jar in the classpath when running. This is basically the same as above. Thus again, you have to use the same major version.
Create an uber jar that already has the Scala stdlib (as well as any other dependency) in it, using sbt-assembly.
Create a native distributable that will set up everything for you, using sbt-native-packager.
For local development and testing option 1 is usually the best one.
For simple projects option 3 is, IMHO, the simplest alternative.
And for very complex projects option 4 is very popular.
Scala newbie here: I am attempting to get started with Scala using Windows 10 (Pro 10.0.18362 Build 18362) Hyper-v Quick Create of Ubuntu (18.04.3 LTS). I installed the JRE and JDK (11.0.4). I installed IntelliJ IDEA 2019.2.4. I added the Plugin for Scala (plugin 2019.2.37). I have left the SBT Executor 1.2.1 disabled for now: it was enabled earlier but it does not seem to affect the results. I tried to create the HelloWorld application (see below). I added the Scala Framework to the Project and, after encountering the error below, the Mavin framework (adding Mavin did not help.) After correcting the error in bulid.sbt it looks like this:
import com.sun.tools.javac.resources.version
name := "HelloWorld"
version := "0.1"
scalaVersion := "2.13.1"
I create a Scala worksheet by right-click on scala folder and selecting Scala Worksheet:
object Hello extends App {
println("Hello, World!")
}
I get a pop-up saying Maven project needs to be imported. This succeeds quickly. I get a second one saying sbt project needs to be imported. This fails:
sbt.librarymanagement.ResolveException: Error downloading org.scala-sbt:zinc-compile-core_2.12:1.3.1
and this error accompanies it:
not found: https://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/org.scala-sbt/util-position_2.12/1.3.2/ivys/ivy.xml
The first ResolveException appears to be about a part of Mavin, but that should be present. This error message is followed by many other "not found" errors, but I assume they all stem from the above errors or are related. I cannot seem to find a solution: most of the information and examples on IntelliJ IDEA Scala on the web are several years (editions) out of date.
It appears Maven apps are to be deployed to Apache Spark. Not my intention, but in the Mavin panel I can successfully clean, validate and compile.
When I Run the Hello.sc app, I get this:
/snap/intellij-idea-community/185/jbr/bin/java -javaagent:/snap/intellij-idea-community/185/lib/idea_rt.jar=37033:/snap/intellij-idea-community/185/bin -Dfile.encoding=UTF-8 -classpath /home/perfwise/ideaProjects/HelloWorld/target/classes:/home/perfwise/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.13.1.jar:/home/perfwise/.ivy2/cache/org.scala-lang/scala-reflect/jars/scala-reflect-2.13.1.jar:/home/perfwise/.ivy2/cache/org.scala-lang/scala-library/srcs/scala-library-2.13.1-sources.jar:/home/perfwise/.ivy2/cache/org.scala-lang/scala-reflect/srcs/scala-reflect-2.13.1-sources.jar Hello
Error: Could not find or load main class Hello
Caused by: java.lang.ClassNotFoundException: Hello
Process finished with exit code 1
I would have expected this to work. Any pointers will be much appreciated.
I'm using Eclipse ScalaIDE and for some reason I'm not able to
import scala.io.StdIn
I'm getting a red squiggly that tells me:
object StdIn is not a member of package io
And I'm seeing that it's not in that scala.io jar file. The ScalaDoc, however says it should be there. I've tried both scala 2.10.4 and 2.11.5. I've used the Eclipse ScalaIDE to create the scala project and I've also created an sbt eclipse project directly using the scalasbt.plugin which I use all the time to manage ScalaIDE dependencies.
sbt "eclipse with-source=true"
Neither way is getting it.
I'm currently taking the Coursera Reactive Programming course and an assignment file has this import. I'm able do compile the project with sbt directly, but Eclipse ScalaIDE is not doing the job. Any clues? There may be good reason why not to use scala.io.StdIn, but my question is why can I not get it to import in the ScalaIDE?
thank you
scala.io.StdIn is new in scala 2.11.x and does not exist in previous versions.
The problem you are likely encountering is that ScalaIDE is not picking up the scala version you are specifying. Since you say that you tried it with 2.10.4, it probably still has that cached or set somewhere and it's failing because it cannot find the specified class.
When trying to import scala.Option in a javafx script, I get the following javafxc error:
cannot access scala.Option.$anonfun$orNull$1
bad class file: scala/Option$$anonfun$orNull$1.class(scala:Option$$anonfun$orNull$1.class)
undeclared type variable: A1
Please remove or make sure it appears in the correct subdirectory of the classpath.
import scala.Option;
I am using Scala 2.8.1, Javafxc 1.3.1_b101, JVM 1.6.0_21-b06, OS Ubuntu 10.10. The same code was working in Scala 2.7.7 .
Later edit:
The same error is reported in case I import scala.immutable.Seq/List/Traversable/Iterable . I have tried the imports in a default Netbeans 6.9.1 JavaFX project which has in the classpath only scala-library.jar.
It reminded me first of #4067, but this one looks quite different.
I would suggest that you try to reproduce the error with 2.8.1 or 2.9 trunk, maybe it is fixed?