I have a JNI shared library written in C and the corresponding Java class in one maven project, and an application using that class in another project. I use the nar-maven-plugin for handling the JNI. Versions: Maven 3.6.0 Java 12 nar plugin 3.6.0 I use the integration tests 3 and 4 that come with nar-maven-plugin as an example. For it 3, I have just updated the POM to be stand-alone and to work with Java 12:
<?xml version="1.0" encoding="UTF-8"?>
<!--
#%L
Native ARchive plugin for Maven
%%
Copyright (C) 2002 - 2014 NAR Maven Plugin developers.
%%
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
#L%
-->
<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>com.github.maven-nar</groupId>
<artifactId>it0003-jni</artifactId>
<packaging>nar</packaging>
<name>NAR JNI Test</name>
<version>1.0-SNAPSHOT</version>
<description>
Simple JNI Library
</description>
<url>http://maven.apache.org/</url>
<properties>
<skipTests>true</skipTests>
<maven-compiler.version>3.8.1</maven-compiler.version>
<surefire.version>2.22.2</surefire.version>
<java.version>12</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<defaultGoal>install</defaultGoal>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler.version}</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
<compilerArgs>
<arg>-Xlint</arg>
<arg>-h</arg>
<arg>${project.build.directory}/nar/javah-include</arg>
</compilerArgs>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>${surefire.version}</version>
<configuration>
<excludes>
<exclude>**/*Test.java</exclude>
</excludes>
<argLine>
<!-- - -illegal-access=permit-->
</argLine>
</configuration>
</plugin>
<plugin>
<groupId>com.github.maven-nar</groupId>
<artifactId>nar-maven-plugin</artifactId>
<version>3.6.0</version>
<extensions>true</extensions>
<configuration>
<cpp>
<debug>true</debug>
</cpp>
<c>
<testOptions>
<testOption>-DTESTOPT="this is a nar-testCompile flag"</testOption>
</testOptions>
</c>
<libraries>
<library>
<type>jni</type>
<narSystemPackage>it0003</narSystemPackage>
<linkCPP>false</linkCPP>
</library>
</libraries>
<javah>
<includes>
<include></include>
</includes>
</javah>
<tests>
<test>
<name>HelloWorld</name>
</test>
</tests>
</configuration>
<executions>
<execution>
<id>default-nar-javah</id>
<phase>none</phase>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
I run mvn install on this project, and it gets installed in my .m2 directory
/home/karsten/.m2/repository/com/github/maven-nar/it0003-jni/:
total 0
drwxr-xr-x 1 karsten karsten 4096 Sep 27 12:20 1.0-SNAPSHOT
-rw-r--r-- 1 karsten karsten 288 Sep 27 12:21 maven-metadata-local.xml
/home/karsten/.m2/repository/com/github/maven-nar/it0003-jni/1.0-SNAPSHOT:
total 20
-rw-r--r-- 1 karsten karsten 250 Sep 27 12:21 _remote.repositories
-rw-r--r-- 1 karsten karsten 3097 Sep 27 12:21 it0003-jni-1.0-SNAPSHOT-amd64-Linux-gpp-jni.nar
-rw-r--r-- 1 karsten karsten 4570 Sep 27 12:21 it0003-jni-1.0-SNAPSHOT.nar
-rw-r--r-- 1 karsten karsten 4086 Sep 27 12:21 it0003-jni-1.0-SNAPSHOT.pom
-rw-r--r-- 1 karsten karsten 925 Sep 27 12:21 maven-metadata-local.xml
and the it0003-jni-1.0-SNAPSHOT.nar contains
META-INF/MANIFEST.MF
META-INF/
META-INF/nar/
META-INF/nar/com.github.maven-nar/
META-INF/nar/com.github.maven-nar/it0003-jni/
it0003/
META-INF/maven/
META-INF/maven/com.github.maven-nar/
META-INF/maven/com.github.maven-nar/it0003-jni/
META-INF/nar/com.github.maven-nar/it0003-jni/nar.properties
it0003/HelloWorldJNI.class
it0003/NarSystem.class
META-INF/maven/com.github.maven-nar/it0003-jni/pom.xml
META-INF/maven/com.github.maven-nar/it0003-jni/pom.properties
Now I use use a cut down version of it 4 to test it, this is the Java file src/main/java/it0004/Hello.java
package it0004;
import it0003.HelloWorldJNI;
public class Hello {
public static void hello()
{
HelloWorldJNI.sayHello();
}
}
and the POM is
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<properties>
<java.version>12</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<maven-compiler.version>3.8.1</maven-compiler.version>
<maven-source.version>2.0.4</maven-source.version>
<nar-plugin.version>3.6.0</nar-plugin.version>
</properties>
<groupId>mygroup</groupId>
<artifactId>myit0004</artifactId>
<packaging>jar</packaging>
<version>1.0.0</version>
<name>Java dependency test</name>
<dependencies>
<dependency>
<groupId>com.github.maven-nar</groupId>
<artifactId>it0003-jni</artifactId>
<version>1.0-SNAPSHOT</version>
<type>nar</type>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler.version}</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
<compilerArgs>
<arg>-Xlint</arg>
</compilerArgs>
</configuration>
</plugin>
</plugins>
</build>
</project>
Note that this POM only handles compilation. The dependency is specified with <type>nar</type>, such that the dependency is found. But the nar file is not in the classPath, so the compilation fails. Output from mvn -X compilecontains
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ myit0004 ---
[DEBUG] Dependency collection stats: {ConflictMarker.analyzeTime=428200, ConflictMarker.markTime=241300, ConflictMarker.nodeCount=118, ConflictIdSorter.graphTime=137600, ConflictIdSorter.topsortTime=62600, ConflictIdSorter.conflictIdCount=45, ConflictIdSorter.conflictIdCycleCount=0, ConflictResolver.totalTime=4391200, ConflictResolver.conflictItemCount=72, DefaultDependencyCollector.collectTime=419330500, DefaultDependencyCollector.transformTime=5343800}
[DEBUG] org.apache.maven.plugins:maven-compiler-plugin:jar:3.8.1:
[DEBUG] org.apache.maven:maven-plugin-api:jar:3.0:compile
[DEBUG] org.apache.maven:maven-model:jar:3.0:compile
[DEBUG] org.sonatype.sisu:sisu-inject-plexus:jar:1.4.2:compile
[DEBUG] org.sonatype.sisu:sisu-inject-bean:jar:1.4.2:compile
[DEBUG] org.sonatype.sisu:sisu-guice:jar:noaop:2.1.7:compile
[DEBUG] org.apache.maven:maven-artifact:jar:3.0:compile
[DEBUG] org.codehaus.plexus:plexus-utils:jar:2.0.4:compile
[DEBUG] org.apache.maven:maven-core:jar:3.0:compile
[DEBUG] org.apache.maven:maven-settings:jar:3.0:compile
[DEBUG] org.apache.maven:maven-settings-builder:jar:3.0:compile
[DEBUG] org.apache.maven:maven-repository-metadata:jar:3.0:compile
[DEBUG] org.apache.maven:maven-model-builder:jar:3.0:compile
[DEBUG] org.apache.maven:maven-aether-provider:jar:3.0:runtime
[DEBUG] org.sonatype.aether:aether-impl:jar:1.7:compile
[DEBUG] org.sonatype.aether:aether-spi:jar:1.7:compile
[DEBUG] org.sonatype.aether:aether-api:jar:1.7:compile
[DEBUG] org.sonatype.aether:aether-util:jar:1.7:compile
[DEBUG] org.codehaus.plexus:plexus-interpolation:jar:1.14:compile
[DEBUG] org.codehaus.plexus:plexus-classworlds:jar:2.2.3:compile
[DEBUG] org.codehaus.plexus:plexus-component-annotations:jar:1.7.1:compile
[DEBUG] org.sonatype.plexus:plexus-sec-dispatcher:jar:1.3:compile
[DEBUG] org.sonatype.plexus:plexus-cipher:jar:1.4:compile
[DEBUG] org.apache.maven.shared:maven-shared-utils:jar:3.2.1:compile
[DEBUG] commons-io:commons-io:jar:2.5:compile
[DEBUG] org.apache.maven.shared:maven-shared-incremental:jar:1.1:compile
[DEBUG] org.codehaus.plexus:plexus-java:jar:0.9.10:compile
[DEBUG] org.ow2.asm:asm:jar:6.2:compile
[DEBUG] com.thoughtworks.qdox:qdox:jar:2.0-M9:compile
[DEBUG] org.codehaus.plexus:plexus-compiler-api:jar:2.8.4:compile
[DEBUG] org.codehaus.plexus:plexus-compiler-manager:jar:2.8.4:compile
[DEBUG] org.codehaus.plexus:plexus-compiler-javac:jar:2.8.4:runtime
[DEBUG] Created new class realm plugin>org.apache.maven.plugins:maven-compiler-plugin:3.8.1
[DEBUG] Importing foreign packages into class realm plugin>org.apache.maven.plugins:maven-compiler-plugin:3.8.1
[DEBUG] Imported: < maven.api
[DEBUG] Populating class realm plugin>org.apache.maven.plugins:maven-compiler-plugin:3.8.1
[DEBUG] Included: org.apache.maven.plugins:maven-compiler-plugin:jar:3.8.1
[DEBUG] Included: org.sonatype.sisu:sisu-inject-bean:jar:1.4.2
[DEBUG] Included: org.sonatype.sisu:sisu-guice:jar:noaop:2.1.7
[DEBUG] Included: org.codehaus.plexus:plexus-utils:jar:2.0.4
[DEBUG] Included: org.sonatype.aether:aether-util:jar:1.7
[DEBUG] Included: org.codehaus.plexus:plexus-interpolation:jar:1.14
[DEBUG] Included: org.codehaus.plexus:plexus-component-annotations:jar:1.7.1
[DEBUG] Included: org.sonatype.plexus:plexus-sec-dispatcher:jar:1.3
[DEBUG] Included: org.sonatype.plexus:plexus-cipher:jar:1.4
[DEBUG] Included: org.apache.maven.shared:maven-shared-utils:jar:3.2.1
[DEBUG] Included: commons-io:commons-io:jar:2.5
[DEBUG] Included: org.apache.maven.shared:maven-shared-incremental:jar:1.1
[DEBUG] Included: org.codehaus.plexus:plexus-java:jar:0.9.10
[DEBUG] Included: org.ow2.asm:asm:jar:6.2
[DEBUG] Included: com.thoughtworks.qdox:qdox:jar:2.0-M9
[DEBUG] Included: org.codehaus.plexus:plexus-compiler-api:jar:2.8.4
[DEBUG] Included: org.codehaus.plexus:plexus-compiler-manager:jar:2.8.4
[DEBUG] Included: org.codehaus.plexus:plexus-compiler-javac:jar:2.8.4
[DEBUG] Configuring mojo org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile from plugin realm ClassRealm[plugin>org.apache.maven.plugins:maven-compiler-plugin:3.8.1, parent: jdk.internal.loader.ClassLoaders$AppClassLoader@446cdf90]
[DEBUG] Configuring mojo 'org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile' with basic configurator -->
[DEBUG] (f) basedir = /home/karsten/svn/myit0004
[DEBUG] (f) buildDirectory = /home/karsten/svn/myit0004/target
[DEBUG] (f) compilePath = [/home/karsten/svn/myit0004/target/classes]
[DEBUG] (f) compileSourceRoots = [/home/karsten/svn/myit0004/src/main/java]
[DEBUG] (f) compilerArgs = [-Xlint]
[DEBUG] (f) compilerId = javac
[DEBUG] (f) debug = true
[DEBUG] (f) encoding = UTF-8
[DEBUG] (f) failOnError = true
[DEBUG] (f) failOnWarning = false
[DEBUG] (f) forceJavacCompilerUse = false
[DEBUG] (f) fork = false
[DEBUG] (f) generatedSourcesDirectory = /home/karsten/svn/myit0004/target/generated-sources/annotations
[DEBUG] (f) mojoExecution = org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile {execution: default-compile}
[DEBUG] (f) optimize = false
[DEBUG] (f) outputDirectory = /home/karsten/svn/myit0004/target/classes
[DEBUG] (f) parameters = false
[DEBUG] (f) project = MavenProject: mygroup:myit0004:1.0.0 @ /home/karsten/svn/myit0004/pom.xml
[DEBUG] (f) projectArtifact = mygroup:myit0004:jar:1.0.0
[DEBUG] (f) session = org.apache.maven.execution.MavenSession@3e84111a
[DEBUG] (f) showDeprecation = false
[DEBUG] (f) showWarnings = false
[DEBUG] (f) skipMultiThreadWarning = false
[DEBUG] (f) source = 12
[DEBUG] (f) staleMillis = 0
[DEBUG] (s) target = 12
[DEBUG] (f) useIncrementalCompilation = true
[DEBUG] (f) verbose = false
[DEBUG] -- end configuration --
[DEBUG] Using compiler 'javac'.
[DEBUG] Adding /home/karsten/svn/myit0004/target/generated-sources/annotations to compile source roots:
/home/karsten/svn/myit0004/src/main/java
[DEBUG] New compile source roots:
/home/karsten/svn/myit0004/src/main/java
/home/karsten/svn/myit0004/target/generated-sources/annotations
[DEBUG] CompilerReuseStrategy: reuseCreated
[DEBUG] useIncrementalCompilation enabled
[DEBUG] Stale source detected: /home/karsten/svn/myit0004/src/main/java/it0004/Hello.java
[INFO] Changes detected - recompiling the module!
[DEBUG] Classpath:
[DEBUG] /home/karsten/svn/myit0004/target/classes
[DEBUG] Source roots:
[DEBUG] /home/karsten/svn/myit0004/src/main/java
[DEBUG] /home/karsten/svn/myit0004/target/generated-sources/annotations
[DEBUG] Command line options:
[DEBUG] -d /home/karsten/svn/myit0004/target/classes -classpath /home/karsten/svn/myit0004/target/classes: -sourcepath /home/karsten/svn/myit0004/src/main/java:/home/karsten/svn/myit0004/target/generated-sources/annotations: -s /home/karsten/svn/myit0004/target/generated-sources/annotations -g -nowarn -target 12 -source 12 -encoding UTF-8 -Xlint
[DEBUG] incrementalBuildHelper#beforeRebuildExecution
[INFO] Compiling 1 source file to /home/karsten/svn/myit0004/target/classes
[DEBUG] incrementalBuildHelper#afterRebuildExecution
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] /home/karsten/svn/myit0004/src/main/java/it0004/Hello.java:[3,14] package it0003 does not exist
[ERROR] /home/karsten/svn/myit0004/src/main/java/it0004/Hello.java:[8,9] cannot find symbol
symbol: variable HelloWorldJNI
location: class it0004.Hello
[INFO] 2 errors
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.606 s
[INFO] Finished at: 2019-09-27T13:28:44Z
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project myit0004: Compilation failure: Compilation failure:
[ERROR] /home/karsten/svn/myit0004/src/main/java/it0004/Hello.java:[3,14] package it0003 does not exist
[ERROR] /home/karsten/svn/myit0004/src/main/java/it0004/Hello.java:[8,9] cannot find symbol
[ERROR] symbol: variable HelloWorldJNI
[ERROR] location: class it0004.Hello
As seen, the nar file of the dependency is not in the classPath, so compilation fails, because it can not find the dependency class. How do I make sure that the nar file is included in the classPath?
