StopWatch#stop(), throwing NPE - spring-mvc

Question

while working on interceptor with SpringMVC I'm getting NPE. I am using log4j.properties and here is the following code of interceptor
ThreadLocal<StopWatch> stopWatchLocal = new ThreadLocal<>();
Logger logger = Logger.getLogger(this.getClass());
#Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object object,
Exception exception) throws Exception {
StopWatch stopWatch = stopWatchLocal.get();
stopWatch.stop();//Line 24
logger.info("Total time taken for processing: " + stopWatch.getTotalTimeMillis() + " ms");
stopWatchLocal.set(null);
}
#Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object object,
ModelAndView modelAndView) throws Exception {
logger.info("Request processing ended on " + getCurrentTime());
}
#Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object object) throws Exception {
StopWatch stopWatch = new StopWatch(object.toString());
stopWatch.start(object.toString());
stopWatchLocal.set(stopWatch);
logger.info("Accessing URL path: " + getURLPath(request));
logger.info("Request processing started on: " + getCurrentTime());
return true;
}
private String getCurrentTime() {
DateFormat formatter = new SimpleDateFormat("dd/MM/yyyy 'at' hh:mm:ss");
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
return formatter.format(calendar.getTime());
}
private String getURLPath(HttpServletRequest request) {
String currentPath = request.getRequestURI();
String queryString = request.getQueryString();
queryString = queryString == null ? "" : "?" + queryString;
return currentPath + queryString;
}
this is the log
j
ava.lang.NullPointerException
at com.webstore.interceptor.PerformanceMontiorInterceptor.afterCompletion(PerformanceMontiorInterceptor.java:24)
at org.springframework.web.servlet.HandlerExecutionChain.triggerAfterCompletion(HandlerExecutionChain.java:167)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1023)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:952)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
interceptor in dispatcherServlet
<mvc:interceptors>
<bean class="com.package.InterceptorClass"></bean>
</mvc:interceptors>
Am I doing something wrong ?
Please Help, is my configuration is broken because I'm not able to get the answer why I am getting NPE