Uncaught TypeError: Cannot read property 'apply' of undefined(sap.m.DatePicker)

Dear All,

I override the java script Date() method to override system date and time from server date and time. The date picker is defaulted with server date but the problem is the datepicker dialog is not opening.

Date = function (Date) {

     MyDate.prototype = Date.prototype;

     return MyDate;

     function MyDate() {

         return currentServerDate;  //currentServerDate is my server date

     }

  }(Date);

I'm getting this below error,

Uncaught TypeError: Cannot read property 'apply' of undefined

(anonymous function) @ UniversalDate.js:6

c.init @ Calendar.js:6

E.extend.constructor @ sap-ui-core.js:152

M.extend.constructor @ sap-ui-core.js:152

E.extend.constructor @ sap-ui-core.js:152

f @ sap-ui-core.js:152

o @ sap-ui-core.js:143

_ @ DatePicker.js:6

b @ DatePicker.js:6

a.onclick @ DatePicker.js:6

a._callEventHandles @ sap-ui-core.js:152

a._handleEvent @ sap-ui-core.js:152

U._handleEvent @ sap-ui-core.js:152

p @ sap-ui-core.js:60

Q.event.dispatch @ sap-ui-core.js:71

v3.handle @ sap-ui-core.js:71

For working Date picker below .js are loadingin network tab.

Calendar.js

CalendarUtils.js

Header.js

Month.js

MonthPicker.js

YearPicker.js

DateRange.js

CalendarRenderer.js

messagebundle_en_US.properties

HeaderRenderer.js

MonthRenderer.js

MonthPickerRenderer.js

But In this overriding case below .js are loading.

Calendar.js

CalendarUtils.js

Header.js

Month.js

MonthPicker.js

YearPicker.js

Please help me to resolve this.

Thanks,

Santhosh Gowda