I am trying to get started with OSGi and want to run a simple hello world app. I followed this tutorial here: https://www.baeldung.com/osgi.
I am able to create a bundle in karaf and run it but unfortunately the System.out.println
logs are not shown.
What am I doing wrong?
Karaf console:
karaf@root()> bundle:list
START LEVEL 100 , List Threshold: 50
ID │ State │ Lvl │ Version │ Name
───┼──────────┼─────┼────────────────┼───────────────────────────────────────────────────────────────────────────────
32 │ Active │ 80 │ 4.4.3 │ Apache Karaf :: OSGi Services :: Event
62 │ Resolved │ 80 │ 1.0.0.SNAPSHOT │ my-app
karaf@root()> bundle:start 62
karaf@root()>
App.java
package de.tom.osgi;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
public class App implements BundleActivator
{
@Override
public void start(BundleContext context) throws Exception {
// TODO Auto-generated method stub
System.out.println("Hello App: start");
}
@Override
public void stop(BundleContext context) throws Exception {
// TODO Auto-generated method stub
System.out.println("Hello App: stop");
}
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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>de.tom.osgi</groupId>
<artifactId>my-app</artifactId>
<packaging>bundle</packaging>
<version>1.0-SNAPSHOT</version>
<name>my-app</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.release>17</maven.compiler.release>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.osgi</groupId>
<artifactId>org.osgi.core</artifactId>
<version>6.0.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
<plugin>
<groupId>org.apache.felix</groupId>
<artifactId>maven-bundle-plugin</artifactId>
<version>5.1.8</version>
<extensions>true</extensions>
<configuration>
<instructions>
<Private-Package>de.tom.osgi</Private-Package>
<Bunde-Activator>de.tom.osgi.App</Bunde-Activator>
</instructions>
</configuration>
</plugin>
</plugins>
</project>
The problem was a typo in the pom.xml
. I wrote Bunde-Activator
instead of Bundle-Activator
. After fixing this everything works now. However I got no error message or anything and just found out through trial-and-error.