Example:

long l 1 = 100000000 l；

In fact, l 1 in memory is just a variable of type long, which exists in the stack and its value is not stored in it. It points to another memory in the heap that actually stores the value. The purpose of adding L is to create a memory of type long in the heap to store values.

So = before and after are actually in two different memory blocks, but there is an invisible pointer to connect them.