Category Archive Beginner

ByBala Manikandan

Overloading and Overriding Methods in Java

Two terms commonly associated with methods in Java are overloading and overriding. These two concepts will be discussed in the following sections.

Method Overloading

Method overloading is the process of defining more than one method having the same name in the same class (or in the same inheritance tree).

Rules to define overloaded methods:

  • The methods must have the same name.
  • The methods must have different argument lists.
  • They may have same or different return types.
  • Their access levels may be same or different.

The correct method to be executed by the system is decided by the Java compiler at compile time, and this is called static polymorphism. The following example demonstrates method overloading:

public class Test {

       public static int add(int a, int b){    //adds 2 numbers

        return a + b;

    }

       public static String add(String a, String b){  //concatenates 2 Strings with a space in between

        return a + ” ” + b;

    }

       public static void main(String[] args){

           System.out.println(“4 + 5 = ” + add(4, 5));

        //calls 1st method

           System.out.println(“Method + Overloading = ” + add(“Method”, “Overloading”));

        //calls 2nd method

    }

   }

The output of the above program is:

4 + 5 = 9

Method + Overloading = Method Overloading

Method Overriding

Method overriding means giving a new definition to an existing method in a class, in one of its subclasses. This is done to redefine the behaviour of objects of the subclass.

Rules to override a method:

  • The overriding method should be present in the subclass of the class in which the overridden method is present.
  • The overriding and overridden methods should have the same name and argument list.
  • The two methods should have the same return type. Or the return type of the overriding method should be a subclass of that of the overridden method.
  • The access modifier of the overriding method must be either the same as or less restrictive than that of the overridden method.

The method to be executed is decided at runtime (not at compile time), and this is called dynamic polymorphism. The following example demonstrates method overriding:

class A {

    public void display(){

        System.out.println(“Executing from class A”);

    }

}

class B extends A {

    public void display(){               //override the method display()

        System.out.println(“Executing from class B”);

   

    }

}

public class Test1 {

    public static void main(String[] args) {

        A objA = new A();

        A objB = new B();              //an A reference, but a B object

        objA.display();

        objB.display();

   

    }

 

}

The above code prints:

Executing from class A

Executing from class B

We have seen the core concepts of ‘Overloading and Overriding’ in Java in this post… Join me as I uncover more Java concepts in subsequent posts…

Bala Manikandan is a 12th grade student in India. He is an Oracle certified Associate(OCAJP 8) Bright and Intelligent, Computers and Math are his favorite subjects!
He hopes to do path breaking research in the Computer Science field!

ByJayanthi

Use cases of Blockchain

Even as the concept of ‘Blockchain’ is bouncing off everyone’s radar and everyone is keen to know more about this trending topic – let us see more about this new and emerging technology. 

Introduction:

‘Blockchain’ is popularly associated with ‘Bitcoin’ cryptocurrency. The Blockchain system shot into prominence and more industry experts took notice of it only after Bitcoin’s surge and ultimately its downfall!

‘Blockchain’ as you might recollect from my earlier post is the shared ledger system. Each transaction is recorded and added to the shared ledger after being approved by the ‘miners’.  The beauty of ‘Blockchain’ is that each miner or node has a copy of the transaction. None of the transactions can be modified or deleted.It allows total transparency of the system with no central authority and promises complete anonymity and security.

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Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

What is Information security?

After having dealt with a huge number of posts on Information security, I thought I will answer one of the fundamental questions about Information security in this post – “What is Information security?” πŸ™‚

Definition:

Information security or “InfoSec” is that discipline of study that broadly seeks to counter and prevent cyber attacks. It also seeks to keep data/information safe by employing different techniques and strategies.

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Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

Social engineering

Introduction:

” 22 bank accounts hacked, β‚Ή5.3 lakh stolen in 48 hours” scream the headlines in a local newspaper on 28th January, 2018 morning.(Source: http://www.thehindu.com/news/cities/bangalore/22-bank-accounts-hacked-53-lakh-stolen-in-48-hours/article22538891.ece)

How did it happen? Two customers were duped of nearly 20,000 Rs and 50,000 Rs by a two conmen(or was it one?) who called the customers in the guise of “bank agents”. They were  asked for their bank details and OTP(one time password) The customers readily obliged since the call was from their “bank”. In a short time, they noticed, that their money was fraudulently withdrawn. 

This is the social engineering technique used by hackers and fraudsters.Let us see this in greater detail.

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Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

Security policies

‘Security policies’ are yet another aspect of Information security that is all around us – but we are hardly aware of it. We will see the meaning of security policy, the reasons for having security policies and some examples of security policies in this post.

A security policy in a nut shell is a document that lays out in detail how an organization is planning to safeguard its business and technological assets.

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Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

Biometrics

‘Biometrics’ is gaining more recognition in today’s world – thanks be to popular organizations embracing it. What is ‘Biometrics’ and what are the different types of biometrics? Read on to find out:

Biometrics – Definition:

Biometrics is uniquely used to identify a person by making use of the distinct characteristics of a person. According to the Michigan State University Biometrics research group, β€œThe field of biometrics examines the unique physical or behavioral traits that can be used to determine a person’s identity”.  These unique traits can be fingerprints, palm scan, hand geometry, retina scan, iris scan, keyboard scan to name a few of them.

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Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

Security trends for 2018!

With the New Year upon us, it is but natural to write about my thoughts on the security trends that might shape 2018! πŸ™‚ So, here goes:

  1. Overall, security trends will closely follow technical trends for a particular year. If AI(Artificial intelligence) , ‘Data analytics’ and IoT(Internet of things) are said to be game changers in the technical industry for 2018 – Infosec trends will definitely exploit the security issues with the mentioned concepts. 
  2. ‘Expect the unexpected’

This might be life’s greatest quote but it holds good for the Infosec industry as well. Equifax, eBay, Uber, University of  Oklahoma, Washington State University were all victims of data breaches of 2017.

These data breaches compromised personal data and 2018 will be yet another year, which steals more personal data. More organizations will lose their precious data or the data will be at the mercy of yet another ingenious way to grab it!

3. ‘Bitcoin’ and other cryptocurrencies:

Will ‘Bitcoin’ hold its sway and continue its meteoric rise? From a humble value of 1000$(for 1 Bitcoin) in the beginning of 2017 to a massive rise of 15,000$(for 1 Bitcoin) by the end of 2017, Bitcoin sure did raise a few eyebrows.  It is quite a possibility that the rise will continue and ‘Bitcoin’ and other cryptocurrencies will be a game changer in the Infosec industry in 2018.

4. Ransomware, fileless malware… what next?

Viruses,phishing emails,Trojan horse were already on the prowl than, that new attacks came to the fore in 2017. We heard new security jargon like ‘ransomware’ and ‘fileless malware’ in 2017 and were scrambling to read all about it , understand it and see if were affected by it in any way. 

2018 will continue to see newer types of attacks and newer security lingo thrown around as hackers get smarter. The more a technology or product is used – the higher the possibility it will be exploited in a novel manner for personal gains. 

5. Data privacy 

Data privacy continues to be a lost issue with every new device monitoring our conversation, location, likes, dislikes. There is a huge electronic virtual  dictionary being built on us with the digital footprint that we are constantly leaving. This will continue into 2018 and beyond!

These are the five points that I think might shake the InfoSec world in 2018!

 

Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

Best technical posts of 2017!

As the year draws to a close, here are my best technical posts of 2017:

  1. Bitcoin and Blockchain: What next?

2. Cyber diplomacy:

3. What is ‘Deep web’?

4. Conflict Resolution at the Work place:

5. Java 8:

 

Warm wishes for a great New Year!

Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

Bitcoin and Blockchain: What next?

It seems every other day has a new headline regarding ‘Bitcoins’. I am sure most of us give a casual glance at this word and wonder where it will go next. From a humble value of $1019 on January 1,2017 the value of Bitcoin has soared to $16,860 till date. This type of meteoric rise will obviously roll a few eyes! πŸ™‚

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I had already written about Bitcoins in my earlier post “Introduction to Bitcoins“. Let’s refresh briefly:

  1. ‘Bitcoin’ is a cryptocurrency
  2. It was created by a highly doubtful ‘Satoshi Nakamoto’ in January 2009
  3. It does not have any physical form
  4. It is largely based on ‘decentralised’ way of transacting business or the ‘blockchain'(no common authority to enforce regulation)
  5. It is accepted in a few countries and some goods can be bought with them
  6. Acceptance by different governments and countries is still an ongoing process
  7. In addition to its legal use,it is also used for illegal activities

What is Blockchain?

‘Blockchain’ is the underlying technology that supports Bitcoin. In simple terms, blockchain is a global ledger. Sending and receiving bitcoins are some example of transactions. A group of transactions will be considered as a ‘block’ which when approved is added to the ‘chain’. This chain cannot be deleted or changed. It is continously added and maintained by all nodes in the network.

Without a regulating authority like a bank, ‘blockchain’ has kept the Bitcoin journey alive for the past 8 years!

 

Future of Bitcoin:

I am no Bitcoin analyst and I do not have the crystal ball, but I can certainly state a few things! πŸ™‚

  1. ‘Bitcoin’ and other cryptocurrencies will continue to hold people’s imagination and urge to invest for at least a certain period of time
  2. Since it is a completely volatile currency, it is not for the faint hearted
  3. Since it is not regulated, people with disposable income are the best individuals to invest in Bitcoin
  4. Even if one would like to invest in Bitcoin, good to start with a small amount
  5. Since the technology itself is evolving and nobody understands its implications fully, better to wait and watch and understand the nitty gritty details of ‘Bitcoin’.

Whether the cryptocurrencies will stand the test of time, the underlying blockchain technology will definitely shake things up in the technology world and will most likely outlive ‘Bitcoin’!

Most of the world’s top universities including Stanford university, Princeton university and e-learning portals like udemy, Coursera have taken notice and started courses in Blockchain. 

 

 

 

Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚

ByJayanthi

Definition of the day: What is malware?

‘Malware’ is  short form for ‘malicious software’. ‘Malware’ encompasses viruses, worms, Trojan horse, ransomware etc

Examples of malware include: Wannacry ransomware

Destruction produced by malware: computers will freeze, the computer can be used to launch attacks, the computer will crash, your data will be maliciously deleted etc.

Jayanthi Manikandan has an undergraduate degree in Computer Science from India and a Master’s degree in Information systems with a specialization in Information security from Detroit, MI, USA.

She has been passionate about Information security and has several years of experience writing on various technical topics. Additionally, she loves to pen a few personal thoughts here as well! πŸ™‚