10+ Interview Questions and Answers

Data types are classifications of data items based on their characteristics.

• Data types define the type of data that a variable can hold

• Java has two categories of data types: primitive and non-primitive

• Primitive data types include int, double, boolean, char, etc.

• Non-primitive data types include arrays, classes, interfaces, etc.

Arrays, strings, and classes are fundamental concepts in Java programming.

• Arrays are collections of similar data types that can be accessed using an index.

• Strings are sequences of characters that are immutable in Java.

• Classes are templates for creating objects that encapsulate data and behavior.

• Arrays and strings are both objects in Java.

• Classes can be used to create custom data types and define their behavior.

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

• OOP focuses on encapsulation, inheritance, and polymorphism

• Objects have attributes (data) and methods (functions)

• Java, C++, and Python are popular OOP languages

• Example: A car object has attributes like color and model, and methods like start and stop

A programming language in Java

• Define a grammar for the language

• Implement a lexer to tokenize the input

• Use a parser to build an abstract syntax tree

• Implement a type checker to ensure type safety

• Generate bytecode or machine code from the AST

• Provide a runtime environment to execute the code

Classes are blueprints for objects, while objects are instances of classes.

• Classes define the properties and behaviors of objects

• Objects are created from classes and have their own unique values for properties

• Classes can be thought of as a template or a blueprint

• Objects are created using the 'new' keyword followed by the class name

• Classes can have static properties and methods, while objects cannot

A collection is a group of objects that can be stored, manipulated, and retrieved as a single unit.

• Collections are used to store and manipulate groups of related objects

• Examples include ArrayList, LinkedList, HashSet, TreeMap

• Collections can be sorted, searched, and filtered

Condition statements are used to execute code based on certain conditions being met.

• Condition statements are typically written using if, else if, and else keywords

• The condition inside the if statement must evaluate to true for the code inside the block to be executed

• Multiple conditions can be checked using logical operators such as && (and) and || (or)

• Switch statements are another way to execute code based on conditions

• Example: if(x > 5) { //code to execute if x is greater th...read more

Servlets are Java classes that handle HTTP requests and responses. XML is a markup language used for data exchange.

• Servlets are server-side components that generate dynamic web content.

• XML is used to store and transport data between systems.

• Servlets can be used to handle form submissions, authentication, and session management.

• XML can be used to define data structures, configuration files, and web services.

• Servlets are part of the Java EE specification, while XML is a languag...read more

Operators are symbols that perform operations on operands in a programming language.

• Arithmetic operators: +, -, *, /, %

• Relational operators: <, >, <=, >=, ==, !=

• Logical operators: &&, ||, !

• Bitwise operators: &, |, ^, ~, <<, >>, >>>

• Assignment operators: =, +=, -=, *=, /=, %=

• Conditional operator: ? :