NullPointerException

[skyGtm]

When system date is 2019-05-01, dpd.show() causes an error

java.lang.NullPointerException: Attempt to read from null array
at com.hornet.dateconverter.DateConverter.getFirstWeekDayMonth(DateConverter.java:640)
at com.hornet.dateconverter.DatePicker.MonthView.setMonthParams(MonthView.java:396)
at com.hornet.dateconverter.DatePicker.MonthAdapter$MonthViewHolder.bind(MonthAdapter.java:292)
at com.hornet.dateconverter.DatePicker.MonthAdapter.onBindViewHolder(MonthAdapter.java:222)
at com.hornet.dateconverter.DatePicker.MonthAdapter.onBindViewHolder(MonthAdapter.java:21)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6781)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6823)
at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5752)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6019)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1557)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1517)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:612)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3924)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3641)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4194)
at com.hornet.dateconverter.DatePicker.DayPickerView.onLayout(DayPickerView.java:139)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at com.hornet.dateconverter.DatePicker.DayPickerGroup.onLayout(DayPickerGroup.java:129)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:639)
at android.widget.FrameLayout.onLayout(FrameLayout.java:574)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:639)
at android.widget.FrameLayout.onLayout(FrameLayout.java:574)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1990)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1844)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1753)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1990)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1844)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1753)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:639)
at android.widget.FrameLayout.onLayout(FrameLayout.java:574)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:639)
at android.widget.FrameLayout.onLayout(FrameLayout.java:574)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:639)
at android.widget.FrameLayout.onLayout(FrameLayout.java:574)
at android.view.View.layout(View.java:16054)
at android.view.ViewGroup.layout(ViewGroup.java:5193)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2510)
at android.view.ViewRootImpl.performTraversals(ViewRootI