"Fail-fast" means that during the software development process, once an exception or error occurs, it will immediately throw an exception or error prompt and stop the program from continuing to execute. This strategy is designed to improve the reliability and stability of software and prevent problems from spreading and causing more serious consequences when problems occur.
In the practice of fail-fast, when the system detects an abnormal state or an error occurs, it will immediately stop the ongoing operation and throw an exception or error prompt, thereby reducing further losses. For example, if a program needs to read a file, but the file does not exist, the program should immediately throw a "file does not exist" exception instead of continuing to execute and causing deeper problems, such as being unable to open the file and causing the program to crash. .
On the other hand, failing fast can also help developers identify and debug problems more quickly. When a problem occurs in the code, fast failure makes the problem appear quickly and be thrown out. Developers can find the problem in time and fix it, thereby improving the maintainability and stability of the system.
In short, "fail fast" is a software development and operation and maintenance strategy that stops further operations by immediately throwing exceptions or error prompts to improve the reliability and stability of the software.
In the Java collection framework, the fast failure mechanism is widely used in collection classes that implement the Iterator interface (such as ArrayList, LinkedList, HashSet, TreeSet, HashMap, etc.). When using an Iterator to traverse a collection, if additions and deletions are made to the collection during the traversal, a ConcurrentModificationException exception will be thrown.
"Fast failure" here means that when the collection is modified, the iterator will immediately throw a ConcurrentModificationException exception to terminate the traversal, instead of or possibly causing greater losses such as traversal delays or even infinite loops.
This mechanism is actually a protection measure to prevent unsafe concurrent operations. For example, when traversing a collection in a multi-threaded environment, without this mechanism, one thread may modify the collection while another thread is traversing it. , which will cause problems such as concurrent access exceptions or data inconsistency. Therefore, this mechanism was introduced in the Java collection framework to ensure the thread safety of collections.
In short, the fast failure mechanism in the Java collection framework ensures the thread safety of the collection by detecting whether concurrent modifications have occurred during the traversal, thereby effectively avoiding potential problems caused by concurrent access.