java.lang.NoClassDefFoundError: org/apache/commons/collections/Transformer

I am not really sure, but i think your error is because of jar versions. Lately apache has changed the package of the new versions of their jars because they implement new functionality or something that is not fully backward compatible. For example the jar commons-beanutils-1.9.2.jar depends on commons-collections-3.2.1.jar (according to this site) and you are using commons-collections-4.4.0.jar. If you are planning using the universe of apache jars, you need to be sure that they are all compatible.

Just add this dependency to your project.

    <dependency>
        <groupId>commons-collections</groupId>
        <artifactId>commons-collections</artifactId>
        <version>3.2.2</version>
    </dependency>

commons-collections4-x.x.jar Add the library to your classpath and try to run again. It will work.

Download the library from: https://mvnrepository.com/artifact/org.apache.commons/commons-collections4/4.1