Java Questions on Collections

Day-1 1. How does HashMap work internally? Answer: High-Level Internal Structure Internally, HashMap uses: Array + LinkedList + Red-Black Tree (Java 8+) Internal Data Structure transient Node K , V >[] table ; This is an array of buckets. Each bucket stores: single node linked list tree nodes Basic Working Flow When you do: map . put ( key , value ); HashMap performs: Calculate hashCode() Calculate bucket index Store value in bucket Handle collision if needed Step-by-Step Example Map Integer , S