Question

Trying to use log4j’s built-in JMSAppender to log messages to a local message queue (ActiveMQ).

I set up a test Driver that has an entry main method and that just instantiates the actual class I want to make the connection:

Driver.java:

public static void main(String[] args) {
    Log4jAmqBridge bridge = new Log4jAmqBridge();
    bridge.run();
}

Log4jAmqBridge.java:

public void run() {
    // ...
}

If I leave my run method totally empty (no instructions) and run the Driver, I just get an empty console (Eclipse). But the second I add the following constructor to run():

JMSAppender appender = new JMSAppender();

I get the following error:

Exception in thread "main" java.lang.NoClassDefFoundError: javax/jms/JMSException
    at test.jmsappender.Log4jAmqBridge.run(Log4jAmqBridge.java:11)
    at test.Driver.main(Driver.java:11)
Caused by: java.lang.ClassNotFoundException: javax.jms.JMSException
    at java.net.URLClassLoader$1.run(Unknown Source) 
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 2 more

I checked the javadoc and it doesn’t look like the JMSAppender no-arg constructor throws an exception.

Does anybody know whats going on?

Edit:
I am actually using Maven to manage my dependencies and have included the following dependency declarations in my pom:

<dependency>
    <scope>compile</scope>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.6.4</version>
</dependency>
<dependency>
    <scope>compile</scope>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>1.6.4</version>
</dependency>

Which puts the following jars under the Maven Dependencies in my project (which are also added to the Eclipse workbench classpath):

• slf4j-api-1.6.4
• slf4j-log4j12-1.6.4
• log4j-1.2.16

Thanks in advance!

Answer 1

Log4jAmqBridge depends on the JMS API.

Add this dependency to your pom.xml :

<dependency>
    <groupId>javax.jms</groupId>
    <artifactId>jms</artifactId>
    <version>1.1</version>
    <scope>provided</scope>
</dependency>

It should solve your problem.