FICO Interview Questions, Process, and Tips

Hashmap is a key-value pair data structure while Hashset is a set of unique values.

• Hashmap allows duplicate values but not duplicate keys.

• Hashset does not allow duplicate values.

• Hashmap is implemented using a combination of hash table and linked list.

• Hashset is implemented using only a hash table.

• Example of Hashmap: {1:'one', 2:'two', 3:'three'}

• Example of Hashset: {'apple', 'banana', 'orange'}

ArrayList is a resizable array while HashMap is a key-value pair data structure.

• ArrayList is ordered and allows duplicates while HashMap is unordered and does not allow duplicate keys.

• ArrayList is accessed by index while HashMap is accessed by key.

• ArrayList is suitable for storing and accessing elements sequentially while HashMap is suitable for fast lookup of values by key.

• Example: ArrayList - List names = new ArrayLi...read more

Abstract class is a class that cannot be instantiated, while an interface is a contract that a class must implement.

• Abstract classes can have implemented methods, while interfaces cannot

• A class can implement multiple interfaces, but can only inherit from one abstract class

• Interfaces are used for achieving multiple inheritance in Java

• Abstract classes are used for creating a base class for other classes to inherit from

• Ex...read more