Selected Java Interview Questions
Sep 30, 2021 · Fundamentals
Understanding the Role of modCount in Java HashMap's Fail‑Fast Mechanism
The article clarifies that the modCount field in java.util.HashMap is used to implement the fail‑fast iterator behavior, explains why the field was volatile in early JDK versions but not in later ones, and shows that ConcurrentModificationException can be thrown even in single‑threaded scenarios when the iterator detects structural changes.
ConcurrentModificationExceptionHashMapJDK
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