Character Set

The character set is a set of alphabets, letters and some special characters that are valid in Java language.

The smallest unit of Java language is the characters need to write java tokens.

These character set are defined by Unicode character set.

Whenever we write any Java program then it consists of different statements. Each Java Program is set of statements and each statement is set of different Java programming lexemes. In Java Programming each and every character is considered as a single lexeme. i.e Basic Lexical Element.

Character Set Consists Of

Alphabets

C abd Java accepts both lowercase and uppercase alphabets as variables and functions.

Uppercase: A B C ................................... X Y Z
Lowercase: a b c ...................................... x y z

Digits

 0 1 2 3 4 5 6 7 8 9 

Special Characters

 +  _  (  )  {  }  [   ]  \  |  /  >   < ;   etc.  

Valid C and Java Characters : Special Characters are listed below

Symbol	Meaning
~	Tilde
!	Exclamation mark
#	Number sign
$	Dollar sign
%	Percent sign
^	Caret
&	Ampersand
*	Asterisk
(	Left parenthesis
)	Right parenthesis
_	Underscore
+	Plus sign
|	Vertical bar
\	Backslash
`	Apostrophe
–	Minus sign
=	Equal to sign
{	Left brace
}	Right brace
[	Left bracket
]	Right bracket
:	Colon
”	Quotation mark
;	Semicolon
<	Opening angle bracket
>	Closing angle bracket
?	Question mark
,	Comma
.	Period
/	Slash

We will learn these ways to create object later.

Objects and Classes in Java

In this page, we will learn about Java objects and classes. In object-oriented programming technique, we design a program using objects and classes.

An object in Java is the physical as well as a logical entity, whereas, a class in Java is a logical entity only.

What is an object in Java

An entity that has state and behavior is known as an object e.g., chair, bike, marker, pen, table, car, etc. It can be physical or logical (tangible and intangible). The example of an intangible object is the banking system.

An object has three characteristics:

• State: represents the data (value) of an object.
• Behavior: represents the behavior (functionality) of an object such as deposit, withdraw, etc.
• Identity: An object identity is typically implemented via a unique ID. The value of the ID is not visible to the external user. However, it is used internally by the JVM to identify each object uniquely.

For Example, Pen is an object. Its name is Reynolds; color is white, known as its state. It is used to write, so writing is its behavior.

An object is an instance of a class. A class is a template or blueprint from which objects are created. So, an object is the instance(result) of a class.

Object Definitions:

• An object is a real-world entity.
• An object is a runtime entity.
• The object is an entity which has state and behavior.
• The object is an instance of a class.

What is a class in Java

A class is a group of objects which have common properties. It is a template or blueprint from which objects are created. It is a logical entity. It can't be physical.

A class in Java can contain:

• Fields
• Methods
• Constructors
• Blocks
• Nested class and interface

Syntax to declare a class:

1. class <class_name>{  
2.     field;  
3.     method;  
4. }  

---

Instance variable in Java

A variable which is created inside the class but outside the method is known as an instance variable. Instance variable doesn't get memory at compile time. It gets memory at runtime when an object or instance is created. That is why it is known as an instance variable.

---

Method in Java

In Java, a method is like a function which is used to expose the behavior of an object.

Advantage of Method

• Code Reusability
• Code Optimization

---

new keyword in Java

The new keyword is used to allocate memory at runtime. All objects get memory in Heap memory area.

---

Object and Class Example: main within the class

In this example, we have created a Student class which has two data members id and name. We are creating the object of the Student class by new keyword and printing the object's value.

Here, we are creating a main() method inside the class.

File: Student.java

1. //Java Program to illustrate how to define a class and fields  
2. //Defining a Student class.  
3. class Student{  
4.  //defining fields  
5.  int id;//field or data member or instance variable  
6.  String name;  
7.  //creating main method inside the Student class  
8.  public static void main(String args[]){  
9.   //Creating an object or instance  
10.   Student s1=new Student();//creating an object of Student  
11.   //Printing values of the object  
12.   System.out.println(s1.id);//accessing member through reference variable  
13.   System.out.println(s1.name);  
14.  }  
15. }  

Test it Now

Output:

0 
null

Object and Class Example: main outside the class

In real time development, we create classes and use it from another class. It is a better approach than previous one. Let's see a simple example, where we are having main() method in another class.

We can have multiple classes in different Java files or single Java file. If you define multiple classes in a single Java source file, it is a good idea to save the file name with the class name which has main() method.

File: TestStudent1.java

1. //Java Program to demonstrate having the main method in   
2. //another class  
3. //Creating Student class.  
4. class Student{  
5.  int id;  
6.  String name;  
7. }  
8. //Creating another class TestStudent1 which contains the main method  
9. class TestStudent1{  
10.  public static void main(String args[]){  
11.   Student s1=new Student();  
12.   System.out.println(s1.id);  
13.   System.out.println(s1.name);  
14.  }  
15. }  

Test it Now

Output:

0 
null

Window 11 will be launch soon.

David Putin ( (7) David Putin | Facebook )

 (M) Microsoft’s upcoming event on June 24 will be all about the next-generation Windows. Although the software giant has not revealed what this upcoming version of Windows is going to be, it looks like the days of Windows 10 will soon be over. Everything available as evidence points to Windows 11, which will replace the long-running Windows 10 as the new platform for PCs. Microsoft has already teased that the next Windows will be visually better and rid of the Windows 95-era icons, but besides the visual overhaul, the next Windows is going to be important as software for the next-generation devices.

Back when Windows 10 arrived, Microsoft said it would not upgrade the Windows version anymore. However, instead, it would change the elements of the operating system to make it up-to-date. And even though Microsoft has not confirmed yet that the next-generation Windows will bring an end to Windows 10, there are certain hints to pick. For example, Microsoft’s June 24 event will kick off at 11 am ET. If this does not give you a hint that the next OS could be Windows 11, you cannot ignore the fact that there is no time conversion for the PT zone. This event is going to be an important one, given both Microsoft CEO Satya Nadella and chief product officer Panos Panay will be presenting it.Nadella previously created the hype around this next generation of Windows by saying that it is going to be the biggest update to Windows in more than a decade. A lot of focus was on developers and creators that are going to find this upcoming version of Windows a lot more productive. Although the specifics are not available, Nadella may be hinting at better compatibility for various formats, support for more advanced technologies and access to tools that creators mostly find useful. Whatever is in the pipeline for Windows 11, rumours suggest that it will be available under Sun Valley, a codename for the update that has been doing rounds on the internet for quite some time.

Sun Valley will bring an overhauled Microsoft Store with probably better design, support for more app structures, and third-party payments systems. And if Microsoft is actually trying to take on Apple, according to the current discourse, it may even lower the commission on purchases made through the Microsoft Store. There may be support for more Android apps that will run on Windows without the need for emulators, alongside support for big-time apps such as Google Chrome that you cannot find in the Microsoft Store right now.

Functionality-wise, Windows 11 is going to take inspiration from Windows 10X, which Microsoft killed last month. Windows 10X was going to be a platform meant for dual-screen devices, such as the Microsoft Surface Neo, but later, the company changed the focus of the OS to support only single-screen laptops. And now that it is cancelled, Microsoft confirmed it is going to use its learnings from Windows 10X and implement them in the next generation of Windows. This means we can see Windows 11-powered foldables and devices with unconventional form factors.

Windows 11 will probably be out by fall this year, typically following the Windows version rollout schedule from the past.👍💤

                                       Chapter  - 2 

                                     Number System 

( D ) Answer the following questions:- 

Ques:-1 Describe Decimal number system with example ?

Ans:- Some examples of decimal numbers are:- A number system which uses digits from 0 to 9 to represent a number with base 10 is the decimal system number. The number is expressed in base-10 where each value is denoted by 0 or first nine positive integers. 

Ques:-2 Briefly explain the hexadecimal number system ?

Ans:- Number systems are the technique to represent numbers in the computer system architecture, every value that you are saving or getting into/from computer memory has a defined number system.

Computer architecture supports following number systems.

• Binary number system
• Octal number system
• Decimal number system
• Hexadecimal (hex) number system

Table of the Numbers Systems with Base, Used Digits, Representation, C language representation:

Number system	Base	Used digits	Example	C Language assignment
Binary	2	0,1	(11110000)2	int val=0b11110000;
Octal	8	0,1,2,3,4,5,6,7	(360)8	int val=0360;
Decimal	10	0,1,2,3,4,5,6,7,8,9	(240)10	int val=240;
Hexadecimal	16	0,1,2,3,4,5,6,7,8,9, A,B,C,D,E,F	(F0)16	int val=0xF0;

Number System Conversions

There are three types of conversion:

• Decimal Number System to Other Base
  [for example: Decimal Number System to Binary Number System]
• Other Base to Decimal Number System
  [for example: Binary Number System to Decimal Number System]
• Other Base to Other Base
  [for example: Binary Number System to Hexadecimal Number System]

Decimal Number System to Other Base

To convert Number system from Decimal Number System to Any Other Base is quite easy; you have to follow just two steps:
A) Divide the Number (Decimal Number) by the base of target base system (in which you want to convert the number: Binary (2), octal (8) and Hexadecimal (16)).
B) Write the remainder from step 1 as a Least Signification Bit (LSB) to Step last as a Most Significant Bit (MSB).

Decimal to Binary Conversion	Result
Decimal Number is : (12345)10	Binary Number is (11000000111001)2

                                                             Make by Aakash

Decimal to Octal Conversion	Result
Decimal Number is : (12345)10	Octal Number is (30071)8

Decimal to Hexadecimal Conversion	Result
Example 1 Decimal Number is : (12345)10	Hexadecimal Number is (3039)16
Example 2 Decimal Number is : (725)10

 

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Description--

Welcome to this course on Practical Ethical Hacking. To enjoy this course, you require nothing but a favorable mindset and a desire to discover. No prior practical knowledge is needed.

In this Practical Ethical Hacking – The Complete Course, you will discover the practical side of ethical hacking. In this course, we will focus just on tools and subjects that will make you effective as an ethical hacker.

In this course, we will cover:

1. What does an ethical hacker do on a day to day basis? What type of evaluations might an ethical hacker carry out?
2. Reliable Notekeeping. An ethical hacker is just as good as the notes she or he keeps. We will talk about the crucial tools you can utilize to keep notes and achieve success in the Practical Ethical Hacking – The Complete Course and in the field.
3. Networking Refresher. This area concentrates on the ideas of computer system networking. We will talk about typical ports and procedures, the OSI design, subnetting, and even walk through a network build with utilizing Cisco CLI.
4. Preliminary Linux. Every great ethical hacker understands their method around Linux. This area will present you to the essentials of Linux and increase into building out Bash scripts to automate work as the course develops.
5. The majority of ethical hackers are skilled in a shows language. You'll find out the ins and outs of Python 3 and by the end, you'll be building your own port scanner and composing exploits in Python.
6. Hacking Methodology. This area introductions the 5 phases of hacking, which we will dive deeper into as the course advances.
7. Reconnaissance and Information Gathering. You'll find out how to collect info on a client utilizing open source intelligence. Even better, you'll find out how to draw out breached qualifications from databases to carry out credential packing attacks, hound subdomains throughout client engagements, and collect info with Burp Suite.
8. Scanning and Enumeration. Among the most essential subjects in ethical hacking is the art of enumeration. You'll discover how to pursue open ports, research study for prospective vulnerabilities, and find out a selection of tools required to carry out quality enumeration.
9. Exploitation Basics. Here, you'll exploit your very first machine! We'll find out how to utilize Metasploit to get to machines, how to carry out manual exploitation utilizing coding, carry out strength and password spraying attacks, and far more.
10. This area takes whatever you have actually discovered so far and challenges you with 10 vulnerable boxes that order in increasing difficulty. You'll discover how an attacker believes and discover brand-new tools and believed procedures along the method.
11. This area talks about the subjects of buffer overflows. This area consists of customized script composing with Python 3.
12. Due to this, Active Directory penetration screening is one of the most crucial subjects you ought to find out and one of the least taught. You will build out your own Active Directory laboratory and discover how to exploit it. You'll likewise discover essential tools like mimikatz, Bloodhound, and PowerView.
13. The 4th and 5th phases of ethical hacking are covered here. What do we do as soon as we have exploited a machine? What are the finest practices for keeping gain access to and cleaning up?

14. In this area, we review the art of enumeration and are presented to a number of brand-new tools that will make the procedure simpler. You will likewise discover how to automate these tools use Bash scripting. After the enumeration area, the course dives into the OWASP Top 10.
15. Wireless Attacks. Here, you will find out how to carry out cordless attacks versus WPA2 and jeopardize a cordless network in under 5 minutes.
16. A subject that is barely ever covered, we will dive into the legal files you might experience as a penetration tester, consisting of Statements of Work, Rules of Engagement, Non-Disclosure Agreements, and Master Service Agreements. We will likewise talk about report writing.
17. Profession Advice. The course concludes with profession recommendations and ideas for discovering a task in the field.

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