IDFC FIRST Bank Interview Questions and Answers

You can sort a class object by implementing the Comparable interface and overriding the compareTo method.

• Implement the Comparable interface in the class and override the compareTo method to compare objects based on roll number.

• Use Collections.sort() method to sort the list of objects based on roll number.

• Example: class Student implements Comparable<Student> { public int compareTo(Student s) { return this.rollNo - s.rollNo; }}

Spring Boot annotations are used to simplify the development process by providing metadata to the Spring framework.

• Annotations like @RestController, @RequestMapping, and @Autowired are commonly used in Spring Boot to define controllers, request mappings, and dependency injection.

• Annotations like @SpringBootApplication are used to bootstrap the Spring application context.

• Annotations like @ComponentScan and @EnableAutoConfiguration help Spring Boot to automatically configure co...read more

PostgreSQL and Oracle SQL differ in terms of licensing, features, performance, and cost.

• PostgreSQL is open-source while Oracle SQL is proprietary.

• PostgreSQL is known for its extensibility and support for advanced features like JSON data types, while Oracle SQL is known for its robustness and scalability.

• PostgreSQL is generally considered more cost-effective for small to medium-sized projects, while Oracle SQL is preferred for large enterprise applications.

• PostgreSQL has a str...read more

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

• HashMap is part of the Java Collections framework.

• It uses hashing to store key-value pairs, allowing for fast retrieval.

• Keys in a HashMap must be unique, but values can be duplicated.

• Example: HashMap<String, Integer> map = new HashMap<>(); map.put("John", 25);

A constructor in Java is a special type of method that is used to initialize objects. It has the same name as the class and no return type.

• Constructors are called when an object of a class is created.

• They can be used to initialize instance variables or perform any other setup required for the object.

• Constructors can be overloaded, meaning a class can have multiple constructors with different parameters.

• If a class does not have any constructors defined, Java provides a default...read more

A Comparator in Java is an interface used to compare objects for sorting purposes.

• Comparator interface is used to define custom comparison logic for objects.

• It has a method called compare() which takes two objects as arguments and returns an integer value based on their comparison.

• It is commonly used with sorting algorithms like Collections.sort() or Arrays.sort().

Functional interfaces in Java are interfaces with a single abstract method, used for lambda expressions and method references.

• Functional interfaces have only one abstract method, but can have multiple default or static methods.

• Examples include java.lang.Runnable, java.util.Comparator, and java.util.function.Predicate.

• Functional interfaces can be used with lambda expressions and method references for concise code.