BC CREATIONOBJECTJAVA

Saved by @IamKishor_P

Vikas Rajput
@vikasrajputin 3 years, 9 months ago 408 views

Save to PDF Share See On Twitter

Five Different Ways to Create Objects in Java

a thread...

1. Using a new keyword.

It's the most popular one. We create an object by using a new operator followed by a constructor call.

Eg:

2. Using the newInstance() method of class "Class":

Eg:

3️. Using the newInstance() method in class "Constructor":

Eg:

Note:

Both the above ways (Shown in 2 and 3),
are known as reflective ways of creating objects.

Fun-fact:

Class's newInstance() method internally uses Constructor's newInstance() method.

4️. Using "Object" class clone() method

The clone() method creates a copy of an existing object.

The clone() method is part of the "Object" class which returns a clone object.

Eg:

When using the clone() method:

Always Remember,

1. The "Cloneable" interface is implemented.
2. The clone() method must be overridden with other classes.
3. Inside the clone() method, the class must call super.clone().

5️. Using Deserialization:

When we deserialize any object then JVM creates a new object internally.

For this, we need to implement the Serializable interface.

Eg:

Conclusion:

We've seen all five ways to create Objects in Java:

1. Using a new keyword.
2. Using Class.newInstance() method
3️. Using Constructor.newInstance() method
4️. Using Object.clone() method
5️. Using Deserialization

Thanks for reading!

More from Vikas Rajput

Vikas Rajput
@vikasrajputin

Java: Beginner Guide to Multithreading

a thread...

Multithreading is a concept of applying multitasking in Java.

Java supports thread-based multitasking.

Java program can be divided into several threads and those threads can be executed in parallel to support multi-tasking.

Two ways to create a thread in Java:

1. By Implementing Runnable Interface
2. By extending the Thread class

Let's create a thread by implementing the "Runnable" interface:

Steps:
1. Implement Runnable Interface
2. Override the run() method, and put your code inside it.
3. Pass the instance of your class to the Thread class constructor.
4. Call the start() method to run your thread.

Let's create a thread by extending the "Thread" class:

Steps:
1. Extend your class with Thread class
2. Override the run() method, and put your code inside it.
3. Instantiate your class.
4. Call the start() method to run your thread.

Vikas Rajput
@vikasrajputin

Java: Acess Modifiers

a thread...

(Cheatsheet Included)

What is an access modifier?

Access Modifiers are a way of providing limited visibility to methods, variables, classes.

Different access modifiers provide different visibility due to which our program because less prone to unwanted changes.

Java has four access modifiers, let's see each one by one

public:
It's the least restrictive access modifier when any class, method, or variable is defined as public then it is accessible from anywhere.

protected:
Protected methods & variables can be accessed within the same package and also accessible to all child classes.

default:
When no access modifier is specified then java treats it as default. With default methods & variables are accessible within the same package.

private:
It's the most restrictive access modifier, when given to any methods & variable it is only accessible within the same class.

Advertisement

Vikas Rajput
@vikasrajputin

Learn Core Java, in 30 days as an Absolute Beginner

a roadmap...

Core Java can be Overwhelming, in the beginning!

Let's see what are those topics you should cover and what you can skip in Core Java.

1. Theoretical Concepts (2 days)

- Features of Java
- JVM, JRE & JDK
- Memory areas in Java
- Basics of how Garbage Collection Works.

2. OOP Concepts (3 days)

- Objects and Classes
- Inheritance
- Polymorphism
- Encapsulation

This topic forms the basis of your Java learning. Spent enough time on this topic and understanding it using real-world examples and some

OOPs Concept in Java

a thread...
— Vikas Rajput (@vikasrajputin) April 4, 2022

3. Primitives data types, Operators & Arrays (3 days)

- Various primitives/non-primitives data types, operators
- What is their use, How to use them
- Various sizes of data types
- Arrays, practice a few of its problems
- 2D/3D arrays and their use cases, practice a few problems

Vikas Rajput
@vikasrajputin

Java: Beginner Guide to Stream API

a thread...

Streams are a way to perform operations on the whole collection of data.

Stream never modifies the source data, it processes it and gives us the result without modifying the original data.

Let's see few popular ways to create stream:

1. Collection. stream()
2. Stream.of(T... values)
3. Arrays. stream()
4. Stream.builder()

Eg:️

Consider stream as a pipeline, where we perform mainly two different operations on the source data:

1. Intermediate Operations(IO)
2. Terminal Operations(TO)

Here's what the stream pipeline looks like:

Source -> Intermediate Operations -> Terminal Operations

Intermediate Operations(IO):

It returns another stream object, after this, we can either call another IO or TO.

Few methods in Stream API for Intermediate operations:
1. filter()
2. map()
3. sorted()

and many more...

Vikas Rajput
@vikasrajputin

Java: Why do we use getter and setter methods?

a thread...

In Java classes, we normally create the getter and setter methods to read and update class level fields respectively.

Let's find out why do we following this practice.

Consider a class "Account", having fields like accountName and accountBalance - to show the name and balance of the account.

As a common practice, both the variables are private and define the public getter and setter method to read and write their values.

Eg:

Using the above example, let's see different use-cases where having getter and setter methods can be game-changing.

1. Validation:

The public getter and setter method act as a single door to access the private fields.

Before updating the value we can run any validation in the setter method and accordingly allow field modification.

Eg:

You May Also Like

$\u015b\u0101kta$

śākta
@LearningShakta

Arya Samaj Exposed ( A Thread)

Today I'm going to expose these so called reviver of Sanatan dharma.

Arya samaj's main book which they treat as their bible is Satyarth Prakasha. Which was written by "Maharishi" Dayanand Saraswati.

Dayanand Condemned Idol worship and blamed it on jains . like really??

The book peddles hate against several Hindu sects.

here is hate against Vaishnavas

Kanekoa
@KanekoaTheGreat

*The Evidence Collection*

There is overwhelming evidence of election fraud. Therefore it is the duty of the Executive, Legislative, & Judicial branches to throw out the fraudulent votes & to honor their oath to protect & defend the Constitution of the USA.🇺🇸🦅

A list below.🔻

1/ Navarro Report: The Immaculate Deception - Six Key Dimensions of Election Irregularities -

2/ Analysis of 3,000 U.S. counties shows Joe Biden received 5.6 % more votes in counties using Dominion Voting Systems (Video) -

3/ Antrim Michigan Dominion Voting Systems Forensics Report -

4/ Evidence Grows: ’20 Election Was Rigged -

Advertisement

$Kestrel \u2664 lwj kin$

Kestrel ♤ lwj kin
@slutxian

MDZS is laden with buddhist references. As a South Asian person, and history buff, it is so interesting to see how Buddhism, which originated from India, migrated, flourished & changed in the context of China. Here's some research (🙏🏼 @starkjeon for CN insight + citations)

1. LWJ’s sword Bichen ‘is likely an abbreviation for the term 躲避红尘 (duǒ bì hóng chén), which can be translated as such: 躲避: shunning or hiding away from 红尘 (worldly affairs; which is a buddhist teaching.) (https://t.co/zF65W3roJe) (abbrev. TWX)

2. Sandu (三毒), Jiang Cheng’s sword, refers to the three poisons (triviṣa) in Buddhism; desire (kāma-taṇhā), delusion (bhava-taṇhā) and hatred (vibhava-taṇhā).

These 3 poisons represent the roots of craving (tanha) and are the cause of Dukkha (suffering, pain) and thus result in rebirth.

Interesting that MXTX used this name for one of the characters who suffers, arguably, the worst of these three emotions.

3. The Qian kun purse “乾坤袋 (qián kūn dài) – can be called “Heaven and Earth” Pouch. In Buddhism, Maitreya (मैत्रेय) owns this to store items. It was believed that there was a mythical space inside the bag that could absorb the world.” (TWX)

Vibhu Vashisth
@VIBHU_Tweet

THE UNTOLD TALE OF THE LESSER KNOWN WARRIORS:JOGRAJ GURJAR & RAMPYARI GURJAR AND HOW DID THEY DEFEAT THE CRUELEST ISLAMIC INVADER, TIMUR LANG.

Timur Lang, was the founder of Timurid Empire. He was born in April 1336 CE, somewhere in central asia.

During his reign, he conquered Persia, Egypt, Central Asia and emerged as the most powerful and heinous ruler. He was a religious fanatic like the rest of the Islamic invaders who tried to invade India.

Timur Lang decided to invade India in 1398 as he heard about India's splendid wealth and had a desire to conquer India which his ancestor Genghis Khan couldn't do.

After Firoz Shah's demise in1388, Delhi Sultanate was in a state of political turmoil.During this time, Timur sent his grandson Pir Mohammad to attack Indian front. He invaded Multan&was able to defeat Iqbal Khan's brother but when he met with resistance,he asked help from Timur.

Iqbal Khan secured his hold on Delhi under Muhammad Tughluq after Firoz Shah died.
Timur provided the required back-up to his grandson with 100000 men approx. Timur sacked and plundered all the cities coming in his way &later in October 1398 reunited with his grandson.

$Joey Tawadrous \U0001f1ee\U0001f1ea$

Joey Tawadrous 🇮🇪...
@joeytawadrous

1) Core attributes of a promising founder worth following:
- Progress/trajectory over time
- How well they lead a team &
- Make the vision happen
- Most impressed when someone is way ahead of where you thought they would be when you check up/see them a few months later.

2) Indie Makers have such a benefit of being small, fast, nimble workers in comparison to big companies.

We can easily pivot and vastly change a project of ours. We can change as we learn more about our users.

Big companies can take months/years for even the smallest of pivots.

3) Before you find a product market you can pivot your project as many times as necessary until you find something that works.

Then you only have one thing to do: scale, scale, scale.

4) Be obsessed with the little details.
- listen to every single person who uses your product
- reply to every single person who emails you about your product
- ask them what they like and do not like
- iterate your product, make changes, pivot if necessary

5) Paul Graham's (@paulg) name came up with a feeling of great admiration! Naturally! It was Paul who said:

In the early stages of a company just;
- write code
- talk/sell to customers to stress test your idea

Nothing else.