Vintech Computer Interview Questions and Answers

Object oriented programming is a programming paradigm that uses objects to represent and manipulate data.

• Object oriented programming focuses on creating reusable code by organizing data and behavior into objects.

• Objects have attributes (data) and methods (behavior) that can be accessed and modified through the object's interface.

• Inheritance allows objects to inherit attributes and methods from parent objects, promoting code reuse and reducing redundancy.

• Polymorphism allows ob...read more

Static and final are both keywords in Java with different meanings.

• Static is used to define a class-level variable or method that can be accessed without creating an instance of the class.

• Final is used to define a constant value that cannot be changed once assigned.

• Static can also be used to define a block of code that is executed only once when the class is loaded.

• Final can also be used to define a class or method that cannot be overridden by a subclass.

Exceptions in Java can be handled using try-catch blocks.

• Enclose the code that may throw an exception in a try block.

• Catch the exception using catch block and handle it appropriately.

• Finally block can be used to execute code regardless of whether an exception is thrown or not.

• Multiple catch blocks can be used to handle different types of exceptions.

• Throwing an exception can be done using the throw keyword.

Multiple inheritance can be achieved through interfaces or mixins.

• Interfaces allow a class to implement multiple interfaces, each with its own set of methods and properties.

• Mixins are classes that contain a set of methods and properties that can be added to other classes.

• Example of interfaces: class MyClass implements Interface1, Interface2 {}

• Example of mixins: class MyClass extends Mixin1(Mixin2(MyBaseClass)) {}

DELETE and TRUNCATE are SQL commands used to remove data from a table.

• DELETE removes specific rows from a table based on a condition

• TRUNCATE removes all rows from a table

• DELETE is slower than TRUNCATE

• TRUNCATE resets the identity of the table

• DELETE can be rolled back, but TRUNCATE cannot

Collection framework is a set of classes and interfaces that provide a standard way to store and manipulate groups of objects.

• It provides interfaces like List, Set, Queue, etc. to store and manipulate collections of objects.

• It also provides classes like ArrayList, HashSet, PriorityQueue, etc. that implement these interfaces.

• It simplifies the process of storing, searching, sorting, and manipulating collections of objects.

• It is a part of the Java API and is widely used in Java ...read more

A foreign key is a column or set of columns in a database table that refers to the primary key of another table.

• It is used to establish a relationship between two tables in a database.

• It ensures referential integrity by preventing invalid data from being inserted into the table.

• It can be used to join tables together to retrieve data from multiple tables.

• For example, a customer table may have a foreign key that refers to the primary key of an orders table.