Capgemini Java Developer Interview Questions, Process, and Tips

Functional interface in Java is an interface with only one abstract method.

• Functional interfaces can have multiple default or static methods.

• Examples include Runnable, Callable, and Comparator interfaces.

• Lambda expressions can be used to implement functional interfaces concisely.

Object-oriented programming concepts in Java

• Oops stands for Object-oriented programming

• It involves concepts like classes, objects, inheritance, polymorphism, encapsulation

• Java is an object-oriented programming language

• Example: class Car { String color; void start() { //code here } }

Polymorphism in Java allows objects of different classes to be treated as objects of a common superclass.

• Polymorphism is achieved through method overriding and method overloading.

• Method overriding allows a subclass to provide a specific implementation of a method that is already provided by its superclass.

• Method overloading allows multiple methods with the same name but different parameters to coexist in the same class...read more

Java datatypes are used to define the type of data that a variable can hold.

• Java has two categories of datatypes: primitive and non-primitive

• Primitive datatypes include int, double, char, boolean, etc.

• Non-primitive datatypes include classes, interfaces, arrays, etc.

• Each datatype has a specific size and range of values it can hold

SQL data types define the type of data that can be stored in a database table columns.

• SQL data types include numeric, character, date/time, and binary types

• Examples: INT, VARCHAR, DATE, BLOB

• Data types determine the storage format, constraints, and operations that can be performed on the data

Count the number of occurrences of a specific string literal within a given string.

• Iterate through the string and check for occurrences of the specified string literal.

• Use the indexOf method to find the position of the specified string literal within the string.

• Keep track of the count of occurrences found.

Actuator is a Spring Boot module that provides production-ready features to help monitor and manage your application.

• Actuator endpoints provide information about your application such as health, metrics, and environment details.

• It allows you to interact with your application through HTTP endpoints to monitor and manage it.

• Actuator can be used to check the health of your application, gather metrics, view thread dump, an...read more

Java 8 features include Qualifier annotation, Comparable vs Comparator, HTTP Methods, and @Autowired annotation in Spring Boot.

• Qualifier annotation in Spring is used to distinguish between beans of the same type.

• Comparable interface is used to define the natural ordering of objects, while Comparator interface is used for custom sorting logic.

• HTTP Methods like GET, POST, PUT, DELETE are used to perform different operati...read more

Linked list and array list are both data structures in Java, but they have key differences in terms of implementation and performance.

• Linked list uses nodes with pointers to the next node, while array list uses a dynamic array to store elements.

• Linked list allows for efficient insertion and deletion of elements, while array list is faster for random access.

• HashMap is a data structure that stores key-value pairs and use...read more

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization helps in reducing data redundancy by breaking down data into smaller, manageable parts.

• It improves data integrity by ensuring that each piece of data is stored in only one place.

• Normalization involves dividing a database into multiple tables and defining relationships between them.

• There are differ...read more