Learn Java in 21 days


Learn Java in 21 days

Anyone can learn Java in 21 days, all they need is dedication and concentration. Java Guide at RoseIndia can help you learn Java in 21 days.

Anyone can learn Java in 21 days, all they need is dedication and concentration. Java Guide at RoseIndia can help you learn Java in 21 days.

Anyone can learn Java in 21 days, all they need is dedication and concentration. Java Guide at RoseIndia can help you learn Java in 21 days. The course is designed in such a way that even a novice can understand the concepts of language and start basic programming within no time.

Java is considered one of the simplest object oriented language, where a programmer does not need to code much. It is fairly easy to learn the language once you understand the concept of the class, method, keyword, function and other important parts of a Java program. The course of Java is meticulously designed by Java experts who have years of experience in Java. The language used here to explain every example is very simple so a person who has no or little knowledge of programming can also understand it.

Besides the chapters, Java developers will also find various Java programs and tutorials that can be downloaded and used by anyone as their part of programming. Java Vaideos section help beginners in creating their own program by watching a Java expert create it.

In order to learn Java in 21 days first you must clear basic concepts and then start coding and slowly move on to more complex programming.

What is Java?

Java is an object oriented programming language that was first developed by Sun Microsystems. The company was later acquired by Oracle. Java is an open source language and hence every day a new program or code is added to its already vast base. Java is based on C, C++. The developers developing Java wanted to create a platform independent language...

What is programming?

Programs are set of instructions that guide a computer to execute a particular task. Programming or coding is a language that is used by operating systems to perform the task.

Oops Concept

OOPs (Object Oriented Programming) is a technique to create programs around objects and data. Every object has some properties. A language like Java follow OOPs concepts if it has Encapsulation, Inheritance and Polymorphism.

Download JDK

Java Development Kit (JDK) can be downloaded for free from the website of oracle and Sun Microsystems. JDK has Java compiler, debugger and other tools to develop Java based applications. There are various versions of JDK available, the latest version of JDK is 7..

Hello world (First java program)

The very first program that a Java developers learns is Hello World program. To write your first program, you need to download JDK and need a simple text editor like notepad.

Understanding Hello World Java Program

Once you have created your first program, you need to understand each and every concept behind it. This is the only way you can learn Java programming. Here you will understand the meaning of public, class, main, String[] args, System.out, etc.

Java Keywords

Here we have described every single keyword that are used in Java programming. Keywords are not used as identifiers. Keywords like abstract, assert, boolean, byte, catch, char, double, enum, etc that are used in the programming have been explained below.

Java Data Types

Data types in Java define a set of permitted values on which the legal operations can be performed. Variables in Java must be declared first so that the memory can be allocated. The value assigned to that variable determines its data type.


A variable refers to the memory location that holds values like: numbers, texts etc. There are four types of variables in Java: Instance variable, Class Variable, Local variable and parameters. Here we have also discussed how to declare a variable.


Here we will discuss about class in Java. A Java class has a defined set of properties and methods. package statement is used to group similar classes. We will discuss in detail about the concept and structure of a class.


Applets are Java program that run on almost all web browsers like Mozilla, Chrome, Internet Explorer, etc. Java Applets are used to make the web site more dynamic and entertaining. Applets can run on any platform and work on all version of Java Plugins.


Java compiler is used to compile the program we have written in a text editor. Compiler javac is a set of program that translates java source code into java byte code. While saving the file, remember that the file name must be same as class name.


Java Interpreter is required on any platform or in any operating system to run Java program. Java interpreter is used to convert Java byte code into machine readable code. Interpreter implements JVM and runs Java applications.


Java debugger finds and fixes bugs in a program. Java debugger is denoted as jdb. Here we have explained in details how Java debugger works.


Here we have discussed the concept of Array in Java. Array class help organize same type of data  in contiguous memory allocations. Array class java.lang.object.

Add Two Numbers in Java

Here we have given an example of how to add two numbers. Integer.parseint is used to convert string types into integer. printin() function is used to print final answer on the console.

Java Control Statements

Here we will discuss about the Control statements of Java. Control statements are of three types: decision making statements (if-then, if-then-else and switch), looping statements (while, do-while and for) and branching statements (break, continue and return). We will discuss how each control statement is implemented and executed.