I want to assign Calendar or Date object which is a global variable in another class. In class Class1 I initialize date object like his:
Calendar date1;
date1 = Calendar.getInstance();
In Class2 I do this:
Calendar date2 = Class1.date1;
Why does it work good if I assign Class1.date1 to date2 inside any method in Class2 but doesn't work if I declare date2 as global variable and assign value Class1.date1? (In this case there will be NullPointerException thrown.)
You simply can't update a global variable without static with another anytype variable because global variables are also class instances and they have to be static to save all the changes that you done on them.