spring MVC controller mappings for each execution are mutually exclusive do ?

spring MVC controller mappings for each execution are mutually exclusive do ?

If a request is mapped in the following code:
fileName = ... + new Date (). getTime () + ...;

handle multiple requests at the same time , the implementation of this code are not mutually exclusive ?
contact with spring time is not long , experts explain
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fileName if it is a local variable , and certainly no problem ; property if it is , then see how many you this Controller entry , multiple entry between the existence of re-entry problems .
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do not recommend using this approach to achieve the unique file name ,
Although spring is a single case of default mode , but you code should appear within a method body ,
So although the spring container controller is a single case , but it always generates a new Date object ,
concern is possible at the same time multiple concurrent access , resulting filename is not unique.
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fileName attention to thread safety issues
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plus other unique identifier to reach the letter .