Getting this error when I try to run jar file that I created : Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Appender - log4j

Question

I am getting an exception when I try to run the jar file that I created for my java application. I am using log4j for logging purpose and I created a custom log that records per cron job transactions.
Then I have written a shell script where I call the jar file. I have put the properties file outside the jar file.
I am running the jar file through a shell script. The command I use is
java -jar app.jar $1
The java application has 2 properties files
1) app.properties
2) sublog4j.properties
The sublog4j properties file has data like this:
log4j.appender.log=package.CustomFileAppender
log4j.appender.log.File=/serverpath/error.log
I have a gut feeling that I am getting error because of package.CustomFileAppender. It is a java file in app.jar but I don't know how to create a custom appender and use it in the external properties file.
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Appender
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2615)
at java.lang.Class.getMethod0(Class.java:2856)
at java.lang.Class.getMethod(Class.java:1668)
at sun.launcher.LauncherHelper.getMainMethod(LauncherHelper.java:494)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:486)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Appender
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

Answer 1

I was getting this error because I was not building the jar file correctly. So what I did is I created an executable jar file and also copied source code when I created the jar. This is how the issue got resolved.