web service does not subtract time in string

Question

the web service receives two string Hora_in and Hora_out, I'm trying to convert those string to date, subtract the conversion of the two strings and convert the result to string, but the error appears.

WS00041: Service invocation threw an exception with message : null; Refer to the server log for more details

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;
import javax.jws.WebService;
import javax.jws.WebMethod;
import javax.jws.WebParam;
import javax.ejb.Stateless;

@WebService(serviceName = "Parking")
@Stateless()
public class Parking {

/**
 * This is a sample web service operation
 * @param Hora_in
 * @param Hora_out
 * @return 
 * @throws java.text.ParseException 
 */
 @WebMethod(operationName = "Reserva")
public String Reserva(@WebParam(name = "Hora_in") String Hora_in,   @WebParam(name = "Hora_out") String Hora_out) throws ParseException {
    String parqueo;
    Locale locale = new Locale("es","CO");
    String hourf = "HH:mm:ss 'Z'";
    SimpleDateFormat format = new SimpleDateFormat(hourf, locale);
    format.setTimeZone(TimeZone.getTimeZone("GMT"));
    Date Hin = format.parse(Hora_in);
    Date Hout = format.parse(Hora_out);
    long diff = Hin.getTime() - Hout.getTime();
    Date difh = new Date(diff);
    DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss 'Z'");  
    dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
    parqueo=dateFormat.format(difh);
    return parqueo;
}

}

below WS00041, the following message appears:

Exceptions details : java.lang.reflect.InvocationTargetException

javax.servlet.ServletException: java.lang.reflect.InvocationTargetException

    at org.glassfish.webservices.monitoring.WebServiceTesterServlet.doPost(WebServiceTesterServlet.java:342)
    at org.glassfish.webservices.monitoring.WebServiceTesterServlet.invoke(WebServiceTesterServlet.java:106)
    at org.glassfish.webservices.EjbWebServiceServlet.service(EjbWebServiceServlet.java:143)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.glassfish.grizzly.servlet.ServletHandler.doServletService(ServletHandler.java:226)
    at org.glassfish.grizzly.servlet.ServletHandler.service(ServletHandler.java:178)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.glassfish.webservices.monitoring.WebServiceTesterServlet.doPost(WebServiceTesterServlet.java:313)
    ... 24 more
Caused by: jaxws.ParseException_Exception: Unparseable date: "10:00"
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.sun.xml.ws.fault.SOAPFaultBuilder.createException(SOAPFaultBuilder.java:147)
    at com.sun.xml.ws.client.sei.StubHandler.readResponse(StubHandler.java:253)
    at com.sun.xml.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:203)
    at com.sun.xml.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:290)
    at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:119)
    at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:92)
    at com.sun.xml.ws.client.sei.SEIStub.invoke(SEIStub.java:161)
    at com.sun.proxy.$Proxy444.reserva(Unknown Source)
    ... 29 more

What should I change to do the subtraction?

Show samples of your input strings. Why a hard-coded `Z` on a time-of-day? Also, given that the error is in `.reflect.` package, I would guess this error has nothing to do with parsing a string of a time-of-day. — Basil Bourque, May 26 '18 at 04:08
When I look at what you are trying to do in your code: try a web search for `java format duration` and get a lot of good inspiration. — Ole V.V., May 26 '18 at 07:25
A [Short, Self Contained, Correct (Compilable), Example](http://www.sscce.org), please? — Ole V.V., May 26 '18 at 07:34

Basil Bourque · Answer 1 · 2018-05-26T04:27:31.123

Reflection?

Your error is likely unrelated to parsing a string of a time-of-day, as the exception relates to a class in the .reflect package.

java.time

You are using the wrong kind of class for a time-of-day. The java.util.Date class is for a date-with-time value. You have no date.

Also you are using troublesome old legacy date-time classes supplanted years ago by the java.time classes.

For time-of-day value, use LocalTime.

LocalTime start = LocalTime.parse( "12:34" ) ;
LocalTime stop = LocalTime.parse( "15:00" ) ;

Time zone with time-of-day only?

I have no ide why your string inputs for a time-of-day would hove a Z on the end. A Z in date-time means UTC. And UTC has no meaning in the context of a time-of-day only value. So I will ignore the 'Z' part of your Question.

`Duration`

Calculate elapsed time using Duration.

Duration d = Duration.between( start , stop ) ;

Locale

No need to specify a Locale when parsing a time-of-day string in standard ISO 8601 format.

A Locale is only needed when localizing/translating where we require a human language and cultural norms.

Date & zone

I suspect that you should be using a date along with your time-of-day, and a time zone as well. But the Question does not explain the business problem, so I am only guessing given your naming.

Be aware that time-of-day calculations are limited to a single generic 24-hour day. You cannot go past midnight into the next day. So your stop time must always be later (greater) than your start time (unless you want a negative number result, going backwards in time).

Learning to debug

Learning to debug is crucial to being a programmer.

When encountering a problem like this, separate out what you suspect is the cause (parsing time-of-day) into a simple little throwaway app. Get your basic functionality working before trying it in the larger scope of your complicated app (web app, servlets, web container, etc.). If your code works in the throwaway app but not the real (complicated) app, then you know the actual cause of the problem almost certainly lies elsewhere.

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

Java SE 8, Java SE 9, Java SE 10, and later
- Built-in.
- Part of the standard Java API with a bundled implementation.
- Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
- Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
- Later versions of Android bundle implementations of the java.time classes.
- For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.