Pregunta de entrevista de Walmart Global Tech

Round 2 - Core Java theory questions - 1. how to make a class immutable? What is the use case? 2. What is the difference between deep copy and shallow copy. 3. how do you declare a singleton class? Write code. 4. Consider below statements - String s1 = "abc" String s2 = new String("abc") String s3 = “abc” what is output of s1==s2 s1==s3 5. set s; s.put(new Student("a", 1)) s.put(new Student("b", 2)) s.put(new Student("a", 1)) what is the size of s 6. how are collisions handled in hashmap? 7. worst case time complexity of inserting element to hashmap 8. using multithreading write program to print output numbers from 1 to 100 even numbers should execute by 1 thread and odd by others. order of numbers 1 - 100 should be maintained