Saubhagya ranjan Das

Java program can be created by using any editor.  The source code in java contains one or multiple number of classes.  Naming a java program Java program must be saved with a .java extension.  The primary name of the program must be same as class name if the class is declared as public.  It can be any name if no class is declared as public.  In one Java program there is only one public class.  How to compile a java program To compile a java program in command prompt (CMD)  Syntax- javac <file_name.java> Example- javac Hello.java How to run a java program To run a java program in command prompt Syntax- java class_name Example- java Hello

How to change the drive in CMD (Command Prompt) To access another drive, type the drive’s letter, followed by : For instance, if you wanted to change the drive from C: to E:, you should type- Example-  E: ⤶ How to change the directory in CMD (CD in Command Prompt) The first command from the list is CD (Change Directory). This command enables you to change the current directory or, in other words, to navigate to another folder from your PC. Syntax- CD <Folder_Name> ⤶ Example- CD Saubhagya ⤶ How to go to the root of the drive in CMD (CD\) The first iteration of the CD command you should know is CD\. It takes you to the top of the directory tree. To see how it works, after you open the Command Prompt, type: Example- CD\ ⤶ How to change the parent directory in CMD (CD..) When you need to go one folder up, use the cd.. command. Let's assume that you’re inside the system32 folder and want to go back to the Windows folder. Type Example-  CD.. ⤶

  Features of Java The primary objective of Java programming language creation was to make it portable, simple and secure programming language. Apart from this, there are also some excellent features which play an important role in the popularity of this language. The features of Java are also known as Java buzzwords . A list of the most important features of the Java language is given below. Simple Object-Oriented Portable Platform independent Secured Robust Architecture neutral Interpreted High Performance Multithreaded Distributed Dynamic Simple Java is very easy to learn, and its syntax is simple, clean and easy to understand. According to Sun Microsystem, Java language is a simple programming language because: Java syntax is based on C++ (so easier for programmers to learn it after C++). Java has removed many complicated and rarely-used features, for example, explicit pointers, operator overloading, etc. There is no need to remove unreferenced objects because there is an Autom...

What is Java?  Java is a high level, robust, object-oriented and secure programming language.Java was developed by Sun Microsystems (which is now the subsidiary of Oracle) in the year 1995. James Gosling is known as the father of Java. Before Java, its name was Oak. Since Oak was already a registered company, so James Gosling and his team changed the name from Oak to Java. Platform: Any hardware or software environment in which a program runs, is known as a platform. Since Java has a runtime environment (JRE) and API, it is called a platform. According to  Sun Microsystems , 3 billion devices run Java. Java Platforms / Editions There are 4 platforms or editions of Java: 1) Java SE (Java Standard Edition) It is a Java programming platform. It includes Java programming APIs such as java.lang, java.io, java.net, java.util, java.sql, java.math etc. It includes core topics like OOPs, String, Regex, Exception, Inner classes, Multithreading, I/O Stream, Networking, AWT, Swing, Reflec...

  The word object-oriented is the combination of two words i.e. object and oriented. The dictionary meaning of the object is an article or entity that exists in the real world. The meaning of oriented is interested in a particular kind of thing or entity. In layman's terms, it is a programming pattern that rounds around an object or entity are called object-oriented programming. The object-oriented programming is basically a computer programming design philosophy or methodology that organizes/ models software design around data, or objects rather than functions and logic. An object is referred to as a data field that has unique attributes and behavior. Everything in OOP is grouped as self-sustainable objects. It is the most popular programming model among developers. It is well suited for programs that are large, complex, and actively updated or maintained. It simplifies software development and maintenance by providing major concepts such as abstraction, inheritance, polymorphism,...

  Procedure Oriented Programming (POP) As the name implies, Procedure Oriented Programming contains step by step procedure to execute. Here, the problems get decomposed into small parts and then to solve each part one or more functions are used. Thus in POP approach, the problem is viewed as a sequence of things to be done, such as, input taking, calculating and displaying. The primary focus stays on functions which will be used to accomplish each task. Procedural language is a type of computer programming language that specifies a series of well-structured steps and procedures within its programming context to compose a program. It contains a systematic order of statements, functions and commands to complete a computational task or program. In procedural programming language programs are divided into smallest parts called functions. In this programming whole program is divided into sub programs, routines, or subroutines by using  top down designing approach. 

  High Level Language High Level computer languages are the advanced development languages in the evolution of computer languages. These languages are designed to make the programming easier and less error-free. High level language uses words and commands along with symbols and numbers. The keywords used in High level languages are similar to English words and can be easily understood by Humans when compared to a Low level language. High-level language is a computer language which can be understood by the users. The high-level language is very similar to human languages and has a set of grammar rules that are used to make instructions more easily. Every high-level language has a set of predefined words known as Keywords and a set of rules known as Syntax to create instructions. The high-level language is easier to understand for the users but the computer can not understand it. High-level language needs to be converted into the low-level language to make it understandable by the co...

Assembly Level Language Assembly language is a middle level language. Assembly level language in computer programming has evolved with the advancements in the machine language. Assembly language uses symbols, such as letters, digits, and special characters. So it is a alphanumeric code. In assembly language, we use predefined words called mnemonics.  Mnemonics in computer terminology to write the instructions. So, comparatively writing a program in Assembly language is more understandable to the Human than Machine Language. As we know that computer only understand the binary codes but assembly language uses alphanumeric codes so that purpose a translator is required to translate it into machine code. The Assembly language code will be converted into a Machine language code with the help of an Assembler so that the computer can understand the binary converted Assembly Language. Assembler Assembler is a translator which converts assembly language code to machine language code. It act...

Low Level / Machine Level Language Fundamentally, the most basic instructions executed by a computer are binary codes, consisting of ones and zeros. Those codes are directly translated into the “on” and “off” states of the electricity moving through the computer’s physical circuits. In essence, these simple codes form the basis of “ Machine Language ”. As Low-level computer language includes only 1’s and 0’s. Machine language is developed by only using binary numbers i.e. 0 and 1. So, the instructions or the statements in this language use a sequence of 0’s and 1’s. This language was used in first and second generation computers. A Low level language is very easily understood by a computer but hard to understand for Humans because all the codes are written in binary number. Example of Machine level language is-100100101001, 1100111010 No need to translate machine level language. Computer directly understands machine language.  Hence no translator is required for this language....

As human beings need a language like Hindi, Telugu, English, or any other regional language or just a body gesture to say something, express feelings and communicate with others. Same a computer also need a language to communicate. A computer cannot understand human languages directly. So, we need a language  to communicate with a computer. We developed several languages as a method of computer communications. Simply, the languages which are used to communicate with a computer are called computer languages.  Definition of a Computer Language A computer language is a group of instructions that are used to create computer programs. This is the brief of computer languages. The main goal is to achieve human-computer interaction. Types of Computer Languages Different types of Computer languages are given below. Low Level / Machine Level Language Assembly Level Language High Level Language

  Components of Computer 1.      Input Unit 2.      Output Unit 3.      Memory Unit 4.      Control Unit 5.      Arithmetical and Logical Unit v Input Unit A computer will only respond when a command is given to the device. These commands can be given using the input unit or the input devices.  For example: Using a keyboard we can type things on a Notepad and the computer processes the entered data and then displays the output of the same of the screen. v Output Unit When we command a computer to perform a task, it reverts for the action performed and gives us a result. This result is called output. There are various output devices connected to the computer. The most basic of which is a monitor. Whatever we write using a keyboard or click using a mouse, is all displayed on the monitor. Thus, the output unit gives us the final result once the entire proces...

A  computer  is an electrical and electronic device that manipulates information, or data. It has the ability to  store ,  retrieve , and  process  data. Electrical devices convert electrical energy into other forms of energy, for example heat, light or sound. Electronic devices control the flow of electrons in order to perform a task. Full form of  computer is   Common Operating Machine Particularly Used for Technical and Educational Research.