/**
 * Basic demo class
 *
 * @param <T>
 *            An explanation on the generic
 */
public abstract class AbsTest<T> {
    /**
     * Basic demo method
     *
     * @param someParam
     *            What to do magic on. See {@link T}
     */
    public abstract void doMagic(T someParam);
}

/**
 * Basic impl class
 */
public class ImplTest extends AbsTest<Object> {
    /*
     * (non-Javadoc)
     *
     * @see AbsTest#doMagic(java.lang.Object)
     */
    @Override
    public void doMagic(Object someParam) {
        // Magic happens
    }
}

org.apache.maven.reporting.MavenReportException:
Exit code: 1 - javadoc: error - com.sun.tools.javac.code.Symbol$TypeVariableSymbol cannot be cast to com.sun.tools.javac.code.Symbol$ClassSymbol