The java system library do not load opencv library

Question

I'm using the opencv library in a java project. I have a simple java project that compiles as a 'jar', and manually adding the opencv library, then, I know that I have to put this code after nothing:

System.loadLibrary(Core.NATIVE_LIBRARY_NAME);

This works well, but now, I need the same application running in a server, so I made a maven simple project that compiles in a 'war' and added opencv in a dependency, but in the line above I get this error.

Caused by: java.lang.UnsatisfiedLinkError: no opencv_java249 in java.library.path

And I guess it is true because is a maven dependency. How I fix this?

Here is my pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.springframework.samples</groupId>
<artifactId>RetinoblastomappSpring</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<description>Tesis de diagnostico temprano retinoblastoma</description>

<properties>

    <!-- Generic properties -->
    <java.version>1.8</java.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

    <!-- Spring -->
    <spring-framework.version>3.2.3.RELEASE</spring-framework.version>

    <!-- Hibernate / JPA -->
    <hibernate.version>4.2.1.Final</hibernate.version>

    <!-- Logging -->
    <logback.version>1.0.13</logback.version>
    <slf4j.version>1.7.5</slf4j.version>

    <!-- Test -->
    <junit.version>4.11</junit.version>

    <!-- OpenCV -->
    <opencv.version>2.4.9-4</opencv.version>

</properties>

<dependencies>
    <!-- Spring and Transactions -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${spring-framework.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>${spring-framework.version}</version>
    </dependency>

    <!-- Logging with SLF4J & LogBack -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${slf4j.version}</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>${logback.version}</version>
        <scope>runtime</scope>
    </dependency>

    <!-- Hibernate -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>${hibernate.version}</version>
    </dependency>


    <!-- Test Artifacts -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>${spring-framework.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
        <scope>test</scope>
    </dependency>

    <!-- OpenCV -->
    <dependency>
        <groupId>nu.pattern</groupId>
        <artifactId>opencv</artifactId>
        <version>${opencv.version}</version>
    </dependency>

    <dependency>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.4.0</version>
    </dependency>



</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.3</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>

UPDATE

I added the library by hand, and is the same, The war is compiling OK, but when I execute it, that line fails and I get the same error.

I read that I have to add opencv to my system variables, but that didn't work

Answer 1

You can solve this issue adding the file "opencv_java249.dll" to the folder java/bin/ (where you have installed java)

(yes this is an answer to me, because I want to help somebody that has troubles on the same thing)