org.apache.jasper.JasperException: An exception occurred processing [/WEB-INF/jsp/athlete_basic_data.jsp] at line [91]

88: %><br>
89: 
90: <%= bean.getContractFirstDay() %><br>
91: <%= ba + bean.getContractLastDay() + be %><br>
92: <% if(bean.hasExtendedRights()){ %><%= bean.getBasicSalary() %> Credits<br><% } %>
93: 
94: <!-- Kranken-Versicherung -->


Stacktrace:
	at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:605)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:498)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:383)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:331)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:583)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:212)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:662)
	at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:540)
	at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:483)
	at de.zent.web.ViewDispatcher.dispatch(ViewDispatcher.java:37)
	at de.zent.web.FrontController.processRequest(FrontController.java:135)
	at de.zent.web.FrontController.doGet(FrontController.java:188)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:489)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:583)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:212)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at de.zent.tm.web.TutorialFilter.doFilter(TutorialFilter.java:55)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at de.zent.tm.web.PermissionCheckFilter.doFilter(PermissionCheckFilter.java:67)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at de.zent.tm.web.BaseFilter.doFilter(BaseFilter.java:37)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:679)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:617)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:934)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1690)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
	at java.lang.Thread.run(Thread.java:750)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 15
	at sun.util.calendar.BaseCalendar.getCalendarDateFromFixedDate(BaseCalendar.java:453)
	at java.util.GregorianCalendar.computeFields(GregorianCalendar.java:2393)
	at java.util.GregorianCalendar.computeFields(GregorianCalendar.java:2308)
	at java.util.Calendar.setTimeInMillis(Calendar.java:1804)
	at java.util.Calendar.setTime(Calendar.java:1770)
	at java.text.SimpleDateFormat.format(SimpleDateFormat.java:943)
	at java.text.SimpleDateFormat.format(SimpleDateFormat.java:936)
	at java.text.DateFormat.format(DateFormat.java:345)
	at de.zent.tm.web.shared.AthleteBean.getContractLastDayOfCurrentContract(AthleteBean.java:337)
	at de.zent.tm.web.shared.AthleteBean.getContractLastDay(AthleteBean.java:300)
	at org.apache.jsp.WEB_002dINF.jsp.athlete_005fdetails_jsp._jspService(athlete_005fdetails_jsp.java:1146)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:583)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:465)
	... 44 more