I have edited the post as I found a typo in the java classpath in the instructions for running example 1.

Either way , as shown below, I am still getting the NoClassDefFoundError for both HelloWorld1 and HelloWorld2.

_java -classpath "lib/slf4j-api-1.7.20.jar;../logback-core-1.1.7.jar;../logback-classic-1.1.7.jar;../logback-examples/logback-examples-1.1.7.jar" chapters.introduction.HelloWorld1
_Exception in thread "main" java.lang.NoClassDefFoundError: chapters/introduction/HelloWorld1
Caused by: java.lang.ClassNotFoundException: chapters.introduction.HelloWorld1
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

java chapters.introduction.HelloWorld1

With this output:
Exception in thread "main" java.lang.NoClassDefFoundError: chapters/introduction/HelloWorld1
Caused by: java.lang.ClassNotFoundException: chapters.introduction.HelloWorld1
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

I checked the list of class files in logback-examples-1.1.7.jar and chapters/introduction/HelloWorld1.class is in the list so I am not sure why this NoClassDef error is coming up. If anyone out there knows. If I find out how to fix this before then, I will post an update.

Thanks a lot