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Interview Q&A / Java

INTERVIEW Q&A · 72 QUESTIONS

Java interview questions

Collections, the JVM, strings, exceptions and threads, the backbone of most campus placement rounds.

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  1. How does a HashSet avoid storing duplicates in Java?

    A HashSet is backed by a HashMap and stores each element as a key. add() uses hashCode to find the bucket and equals to check for an existing equal element; if one exists the add returns false and nothing is stored.

    BeginnerQuick answer1 min read