Overview of Core Java

Java Step by Step Tutorial
Overview of Core Java Interview Questions

1) What is Java?

Java is a Programming Language and a Platform

Java is used as a programming to develop Software Applications, and It is used as Software Platform to run 
Java Applications.
2) What is Core Java?

Java has 3 important Editions

i. Java Standard Edition / Core Java (* Old name J2SE)
ii. Java Enterprise Edition / Advanced Java (*Old name J2EE)
iii. Java Micro Edition (* Old name J2ME)
3) What are Java Language Basics?

i) Comments
ii) Data Types
iii) Modifiers
iv) Variables
v) Operators
vi) Flow Control (Contional, Loop, and Branching)
vii) Strings
viii) Arrays
ix) IO Operations, and File Handling
x) Methods (pre-defined, and User defined)
xi) Regular Expressions
xii) Exception Handling
xiii) Object Oriented progrramming
1) Inheritance
2) Polymorphism
3) Absrtaction
4) Encapsulation
4) How to Use Java?

Java is an Open Source Software and Platform independent,

For Software Development download and install JDK (includes JRE and JVM) Software,
For Run-time (to run Software Applications that developed in Java) download and install JRE (includes JVM)
Note: We can run Java byte code on any supported platform.
5) What is Comment in Computer Programming?

Generally Comment is an English word, In computer programming we use Comments for Code documentation,
> To make the Code Readable
> To make the Code disable from Execution.
6) What are Java Data Types?

A Data Type is a classification of the type of data that a variable or object can hold in computer programming.

Java supports two categories of Data Types,

i) Primitive Data Types
ii) Reference Data Types.
7) What are Java Variables?

A named memory location to store temporary data within a program.

Java has three types of Variables,
i) Local Variables
ii) Instance Variables
iii) Class / Static Variables
8) What are Java Operators?

Operators are used to perform Mathematical, Comparison and Logical Operations.

Categories of Operators in Java
i) Arithmetic Operators
ii) Relational Operators
iii) Assignment Operators
iv) Bitwise Operators
v) Logical Operators
vi) Miscellaneous Operators
9) What are Java Control Flow Statements?

Java has Three Types of Control Flow Statements,

i) Conditional Statements
ii) Loop Statements
iii) Branching Statements
10) What are Java Methods?

Methods are also known as Functions.

> In Structured Programming (Ex: C Language) we use Functions (Built-in and User defined)
> In Object Oriented Programming (Ex: Java Language) we use Methods (Built-in and User defined)

Two types of Methods in Java

i) Built in Methods
Number Methods
Character Methods
String Methods
Array Methods etc...
ii) User defined Methods
Method with returning value
Method without returning any value.
11) What are Fundamentals of OOPS?

Four fundamentals of OOPS (Oriented Programming System) Concepts are,
i) Inheritance
ii) Polymorphism
ii) Abstraction
iii) Encapsulation


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