Interview Questions and Answers

Object-oriented programming (OOP) is a programming paradigm that uses objects to represent and manipulate data.

• Encourages modular and reusable code

• Provides a clear structure and organization to the code

• Allows for easier maintenance and updates

• Supports code reusability through inheritance and polymorphism

• Enables encapsulation, hiding the internal details of an object

• Promotes code extensibility and scalability

• Facilitates collaboration and teamwork in software development

Update query is used to modify existing records in a database table.

• Update query is a SQL statement that allows you to change the values of one or more columns in a table.

• It is used to update existing records based on specified conditions.

• The syntax of an update query includes the UPDATE keyword followed by the table name, SET keyword to specify the columns to be updated, and WHERE clause to specify the conditions for updating.

• Example: UPDATE employees SET salary = 50000 WHER...read more

JVM is a virtual machine that executes Java bytecode. JRE is a runtime environment that includes JVM and necessary libraries. JDK is a development kit that includes JRE and tools for developing Java applications.

• JVM stands for Java Virtual Machine and is responsible for executing Java bytecode.

• JRE stands for Java Runtime Environment and includes JVM and necessary libraries to run Java applications.

• JDK stands for Java Development Kit and includes JRE along with tools for devel...read more

Method overloading is the ability to define multiple methods with the same name but different parameters.

• Method overloading allows a class to have multiple methods with the same name but different parameters.

• It helps in improving code readability and reusability.

• The compiler determines which method to call based on the number, type, and order of the parameters.

• Example: int add(int a, int b) and int add(int a, int b, int c) are overloaded methods.

Inheritance is a concept in object-oriented programming where a class inherits properties and behaviors from another class.

• Inheritance allows for code reuse and promotes modularity.

• The class that is being inherited from is called the superclass or base class.

• The class that inherits from the superclass is called the subclass or derived class.

• The subclass can access the public and protected members of the superclass.

• Inheritance can be single, where a subclass inherits from only...read more

Triggers in SQL are database objects that are automatically executed in response to specified events.

• Triggers are used to enforce business rules, maintain data integrity, and automate tasks.

• They can be defined to execute before or after an INSERT, UPDATE, or DELETE operation.

• Triggers can be written in SQL or a procedural language like PL/SQL or T-SQL.

• Examples of trigger events include inserting a new record, updating a specific column, or deleting a row.

• Triggers can be used t...read more