JOSCOTEC Engineering Services Interview Questions and Answers

RDBMS stands for Relational Database Management System. It is a type of database management system that stores data in a structured format.

• RDBMS is used to manage relational databases, where data is stored in tables with rows and columns.

• Examples of RDBMS include MySQL, Oracle, SQL Server, and PostgreSQL.

• RDBMS uses SQL (Structured Query Language) for querying and managing data.

• It ensures data integrity through relationships between tables.

• RDBMS allows for efficient data retri...read more

Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.

• Abstract class can have constructors, fields, and methods, while interface cannot have any of these.

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

• Abstract classes are used to define a common behavior for subclasses, while interfaces are used to define a contract for classes to implement.

• Example: Abstract class 'Animal' with ab...read more

A wrapper class in Java is a class that wraps around a primitive data type and provides additional methods and functionalities.

• Wrapper classes are used to convert primitive data types into objects.

• They provide methods to access the value of the wrapped primitive type.

• Examples include Integer, Double, Boolean, etc.

SQL provides benefits such as data retrieval, data manipulation, data security, and data consistency.

• Efficient data retrieval: SQL allows for quick and easy retrieval of specific data from databases.

• Data manipulation: SQL enables users to update, insert, and delete data in databases.

• Data security: SQL provides features like user authentication and access control to ensure data security.

• Data consistency: SQL helps maintain data integrity by enforcing constraints and relationsh...read more

Concurrent transactions are multiple transactions that are executed simultaneously in a database system.

• Concurrent transactions can lead to issues like data inconsistency and conflicts.

• Database systems use techniques like locking and timestamping to manage concurrent transactions.

• For example, if two users try to update the same record at the same time, conflicts may arise.