static用在类的方法中，我现在的问题是static的这个变量是保存在内存中，
1 具体保存在内存中的哪个地方？
2 这个static的变量多长时间被收回？
3 过多的使用的static会不会造成服务器内存不够？
4 不同的用户的static变量为什么会互不影响？
When you declare a class method/variable as static, it is bound to and shared by the class, not the object. From a memory management perspective what this means is that when the class definition is loaded into the heap memory, these static objects are created there. When the class's actual object is created in the stack memory and when updates on the static properties are done, the pointer to the heap which contains the static object gets updated. This does help to reduce memory but not by much.
From a programming paradigm, people usually choose to use static variables for architectural advantages more than memory management optimization. In other words, one might create static variables like you mentioned, when one wants to implement a singleton or factory pattern. It provides more powerful ways of knowing what is going on at a "class" level as opposed to what transpires at an "object" level.
static的是保存在内存中的吧，过多的使用应该会造成内存不足?