Expleo Group Java Developer Interview Questions and Answers for Freshers

HashMap is a data structure in Java that stores key-value pairs and allows for fast retrieval of values based on keys.

• HashMap is part of the Java Collections framework.

• It implements the Map interface and uses hashing to store elements.

• Example: HashMap map = new HashMap<>(); map.put("key", 1); int value = map.get("key");

Internal implementation of set is typically based on hash table or balanced tree data structures.

• Sets are typically implemented using hash tables for faster access and retrieval of elements.

• Some sets, like TreeSet in Java, are implemented using balanced trees to maintain elements in sorted order.

• Internal implementation may vary based on the specific set implementation in a programming language.