Complete BlueJ Java Programming Course for Class 9th Students

About the Computer

The Computer is an electronic device that takes Inputs (Instructions) and produces the required output by processing the input data. it is a high-speed electronic device that can perform arithmetically as well as logical operations. computers are very fast, accurate, and productive devices. there are 5 basic operations of a computer, such as Input, processing, output, storage, and control.

Parts of Computer

Software and hardware are two essential parts of a computer. both hardware and software are interdependent on each other.

Hardware

The physical parts of the computer system are called the hardware component. It helps in data storage and running the software. The hardware component includes a CPU, Hard disk, Keyboard, Printer, Mouse, Speaker, etc.

Software

Software is a computer program or collection of instructions that perform the task by using the instructions. It helps the user to interact with the computer through hardware components. The software components of a computer include Windows, Mac Operating System, Microsoft Word, Firefox, etc. Software is further classified into two categories - System Software Application Software

History of Computer

In the early days, people use stones, bones, and sticks for counting. A brief history of computer development is given here.

ABACUS

The history of computers started with the invention of ABACUS approximately 4000 years ago by the Chinese. It was the first calculating tool which was made up of wood and metal rods. On a wooden rack metal rods with beads are connected. when these rods are moved, it did arithmetic calculations on specific guidelines.

Napier’s Bone

After Abacus, John Napier invented a manually-operated calculating device. for the first-time decimal points were used in this machine.

Pascaline

Blaise Pascal, who is a French Mathematician and Philosopher invented Pascline between 1642-1644. Pascaline is also called Arithmetic or Adding Machine.

Difference Engine

In the 1820s, Charles Babbage invented the Difference Engine which is known as the “Father of Modern Computer”. A Different Engine is a simple Mechanical Computer that could do basic calculations.

Analytical Engine

This machine was also invented by Charles Babbage in the year 1830. Punch-Cards had used as the input devices in Analytical Engine for the first time. It has the capacity to save Data in permanent memory.

Mark I

The invention of Mark I was a pioneer in the history of computers. It was built in 1944, by IBM and Harvard as a joint partnership.

Mark, It was the first Digital Computer.

Generations of Computer

Computers are divided into 5 Generations on the basis of the development of Computer technologies. these are -

First Generation (1946-1959): Vacuum Tubes

The first generation computers worked very slowly. It was also very huge and expensive. Vacuum tubes are used in first-generation computers as the basic part of memory and CPU (Central Processing Unit). Examples of first-generation computers are ENIAC, EDVAC, UNIVAC I, IBM-701, and IBM-650.

Second Generation (1956-1963): Transistors

Transistors were used in second-generation computers. It made computers faster in comparison to first-generation computers. The transistor used by these computers consumed very less power, it was also very cheap and compact. Examples of second-generation computers are IBM 1620, IBM 7094, and UNIVAC 1108.

Third Generations (1964-1971): Integrated Circuits

ICs (Integrated Circuits) were used Instead of transistors in third-generation computers. The use of ICs has increased the power of computers and also reduced the cost. In the third generation, the size of computers also decreased and became more reliable and efficient. IBM-360 series and Honeywell-6000 series are examples of third-generation computers.

Fourth Generation (1971-Present): Microprocessors

In the fourth generation, VLSI (very large scale integrated) was used it is a chip that contains millions of “Transistors”. because of the use of chips, this generation of computers became very fast and adorable. This 4th Generation computers also became more compact and powerful. It also uses the C and C++ programming languages.

Some examples of fourth-generation computers are DEC 10, CRAY-X-MP, and STAR 1000.

Fifth Generation (Present and Beyond): Artificial Intelligence

Fifth-generation computers have replaced the VLSI and used ULSI (Ultra Large scale Integration). These computers are used C, C++, JAVA, and Python programming languages.

Examples of fifth-generation computers are Desktop, laptops, Chromebook, Notebook, and UltraBooks

Advantages of Computer

• Reliability - It is very reliable and friendly to use.
• Communication - A computer helps us to communicate with each other by various means.
• Productivity - By using its speed and accuracy a computer gives very productive results.
• Multitasking - Multitasking is one of the main advantages of computers which simply means that they can do multiple tasks at the same time.
• Speed - The Incredible speed of computers is, an asset for human life. A computer can do trillions of work within seconds.
• Accuracy - A computer doesn’t work very quickly but it also has great accuracy. Due to this, we can believe in computers for our work.
• Huge Storage - A man has not the capacity to remember all the data but a computer can store a large number of data very securely

Disadvantages of Computer

The disadvantages of computers are -

• Virus and Hacking attacks
• Online Cyber Crime
• High Cost
• Reduction in Employment Opportunities
• Distractions
• Bad impact on Eye and Body Posture

Programming Languages

Language is the medium of communication, that is used to express our thoughts and feeling to others. Just like language, Programming Languages are also a type of language, that is used by programmers to communicate with computers. Programming Languages are the set of guidelines that are written in a particular language like C, C++, JAVA, or Python). Programmers use programming languages to develop computer software, mobile applications, & websites, etc.

Types of Programming Languages

There are 3 types of programming languages.

1. Machine Language
2. Assembly Language
3. High-Level Language

Machine Level Language: 

Machine Level Language is also called the Low-level programming language. It is simply based on the binary (base 2) or Hexadecimal (base 16) form that makes it easy to read or execute. A computer doesn’t require any medium to understand Machine-level language. A programmer can execute a program in machine-level language very fastly in compared to High-level languages.

Assembly languages:

Assembly languages are also low-level programming languages, but they can’t communicate directly with a computer. It needs an assembler (mediator) to convert ASM( Assembly language) into machine language.

some examples of Machine Level Languages are :

High-level languages (HLL):

High-level languages are user-friendly for developing mobile applications, software, websites, and programs. HLL needs a compiler to communicate with the Computer or execute the program. A compiler converts the program into machine language. This programming language is very easy to learn, write and execute for the programmers.

Examples of High-level Programming languages are Python, Java, C#, C++, COBOL, PHP, FORTRON, JavaScript, etc.

List of some programming languages, which are widely used in the world.

PYTHON: It is very simple to learn, understand and write programs. Python is a user-friendly programming language as it executes the code line by line. It is also a machine-independent programming language.

JAVA: It is also very easy and simple to learn, write and compile. It is a multi-tasking programming language. A major advantage of the Java language is that a single program can be run on many platforms. It is considered the safest language.

C: C is the oldest, most popular, and widely used programming language. It is considered the base of all programming languages. C programming language has the features of both Low-level and High-level Programming languages. It is also very easy to learn but difficult to find errors.

C++: The base of the C++ programming language is C with additional features. That's why it is also called the advanced version of the C Programming language. It was developed in 1980 by Bjarne Stroustrup. C++ programming language is not as secure as JAVA/Python.

C#, PHP, JavaScript, Node.js, React.js, and R programming are also very popular and widely used in the modern world.

The converter is a type of software, that is used to convert any programming language into machine code. It is also known as a translator. It is 3 types -

1. Compiler
2. Interpreter
3. Assembler

What is Compiler?

A compiler is special software that works as a translator to change a high-level language program into machine language. In other words, we can say that a compiler converts source code into object code. But sometimes compilers change the high-level language into assembly language. It is also called the intermediate step. A compiler translates the whole program at a single time, i.e., it generates the object code for the program along with a list of errors.

Working methods of a compiler:

• First Compiler accepts high-level program input.
• After it checks the program for any errors.
• If there are any errors, then the compiler displays a list of errors.
• If there is no error in the program, then the compiler converts High-level programs into Low-level language.

What is an Interpreter?

The interpreter is a translator program, that is used to convert the high-level programming language into the low-level programming language. It translates the code line by line, i.e., it converts one line, executes the instruction, and then repeats the procedure for the remaining instructions. If the interpreter found any bugs in the program, it removes them immediately. Interpreter programs are mostly liked by new programmers and are slow in execution speed.

Working methods of an interpreter:

• First Interpreter accepts high-level programs as input.
• After it checks the first statement of the program for error if there is not an error in the first statement then the interpreter converts the statement into low-level language.
• If found any error, then it displays that error.
• This process is repeated until all the stages of the program are checked.

What is an Assembler?

Assemblers were developed to convert the assembly language program (it is a computer 2nd gen program that uses mnemonic codes and symbols instead of binary) into machine language. A program written in assembly language is called the source program and the program converted into machine language by the assembler is called an object program or object code.

Difference Between Compiler, Interpreter & Assembler:

BlueJ is a Java Editor. It is open-source software for Java coding. It is an IDE (). with the help of this software, we can easily write the java code and compile the code and easily debug the program. This software is designed by BlueJ Team. The original author of this software is Michael Colling. It is a cross-platform software.

First, we will go to the official website of Blue J (https://www.bluej.org/) to download & Installing the Blue J Software. after this the home page of the official website will be open. then find the download button & Choose your laptop/desktop's operating system. If your operating system is Windows, click on the windows card, if your operating system is Mac OS X, click on the Mac OS X card, If your operating system is Ubuntu/Debian, click on the Ubuntu/Debian Card, if your system has other operating systems, then click on the other card & download the software.

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