Question

Below is the ear structure

ex.ear
|
|_lib-util.jar--CommonUtil.class,CommonException.class etc.
|
|
|
ejb.jar
web.war

When I call this specific class like this (CommonUtil.map(empDto)) in WEB and EJB layer classes then we are getting a NoClassDefFoundError. Remaining all classes which are in Util.jar are all getting called normally. Why are we getting this error only for this class?

EmployeeDTO empDto = new EmployeeDTO();
empDto.setId(1);
empDto.setName("john");
CommonUtil.map(empDto);

public class CommonUtil {

    private static Mapper mapper = new BeanMapper();
    private static CommonUtil instance = new CommonUtil();

    private CommonUtil() {
        super();
    }

    public static <T> T map(Object source) {
        T target = mapper.map(source);
        return target;
    }

    public static <T> T map(Object source) {
        mapper.map(source);
        return target;
    }
}

Answer 1

Generally speaking the NoClassDefFoundError happens if an Exception occurs during the static initialization. Please check the log prior NoClassDefFoundError carefully if any exception happened during instantiating BeanMapper or CommonUtil.