Struts2 - addFieldError на двойной

Question

У меня проблема с методом validate () в классе действий.

if (checkerObj.getSalesRetailPrice().toString().trim().length() == 0) {
        addFieldError("salesRetailPrice", "Must be positive.");
    }

Мой, если не работает. Это возвращает java.lang.NullPointerException Какое решение возможно для этой проблемы? Ошибка ниже

type Exception report

сообщение

description Сервер обнаружил внутреннюю ошибку, которая не позволила ему выполнить этот запрос.

исключение

java.lang.NullPointerException checker.compute.action.PriceCheckerAction.validate (PriceCheckerAction.java:40) com.opensymphony.xwork2.validator.ValidationInterceptor.doBeforeInvocation (ValidationInterceptor.java:251) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept (ValidationInterceptor.java:263) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept (AnnotationValidationInterceptor.java:68) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept (MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept (ConversionErrorInterceptor.java:138) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept (ParametersInterceptor.java:249) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept (MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept (ParametersInterceptor.java:249) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept (MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept (StaticParametersInterceptor.java:191) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) org.apache.struts2.interceptor.MultiselectInterceptor.intercept (MultiselectInterceptor.java:73) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) org.apache.struts2.interceptor.CheckboxInterceptor.intercept (CheckboxInterceptor.java:91) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) org.apache.struts2.interceptor.FileUploadInterceptor.intercept (FileUploadInterceptor.java:252) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept (ModelDrivenInterceptor.java:100) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept (ScopedModelDrivenInterceptor.java:141) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept (ChainingInterceptor.java:145) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept (PrepareInterceptor.java:171) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept (MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept (I18nInterceptor.java:176) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept (ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246)com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept (AliasInterceptor.java:193) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept (ExceptionMappingInterceptor.java:187) com.opensymphony.xwork2.DefaultActionInvocation.invoke (DefaultActionInvocation.java:246) org.apache.struts2.impl.StrutsActionProxy.execute (StrutsActionProxy.java:54) org.apache.struts2.dispatcher.Dispatcher.serviceAction (Dispatcher.java:546) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction (ExecuteOperations.java:77) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter (StrutsPrepareAndExecuteFilter.java:91) note Примечание Полная трассировка стека основной причины доступна в журналах Apache Tomcat / 7.0.68.