BC STREAMAPI

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Vikas Rajput
@vikasrajputin 4 years, 2 months ago 802 views

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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...

Examples:

filter() - filters out the data based on any boolean condition - below we're filtering elements starting with the letter a.

map() - performs some given operation on the whole data set - below we're converting every element to upper case.

Terminal Operations(TO):

It's the last operation done on stream that's why it's called terminal.

This operation returns the final result.

Few methods in Stream API for Terminal operations:
1. collect()
2. count()
3. forEach()

and many more...

Examples:

collect() - collects the elements in the given collection as shown below in the first case it is returning data in the form of a list.

count() - counts the no of the element in the stream and returns in the form of long.

Remember:

A Single pipeline can have multiple Intermediate Operations.

And only a single Terminal Operations.

Eg:
Below, we've used two Intermediate Operations i.e. filter() and map() but only used single Terminal Operation i.e. count().

More from Vikas Rajput

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.

Vikas Rajput
@vikasrajputin

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.

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Vikas Rajput
@vikasrajputin

OOPs Concept in Java

a thread...

OOP Concepts are very common in Software Engineering.

All the OOP languages like Java, Python, C++, .Net, etc. have this concept.

In this thread, we'll try to understand it from Java's standpoint.

There are six different concepts in OOP:

1. Object
2. Class
3. Inheritance
4. Encapsulation
5. Abstraction
6. Polymorphism

Let's understand them one by one...

Object:

Look around you, whatever you see can be considered an Object.

For eg: The chair you are sitting on, the table, your computer, your house, windows, your pet, you yourself!

An object has Behaviour (things it does or performs) and Attributes (things that describe it).

Example:

Note: B = Behavior, A = Attribute

Chair:
B - Moves, Adjust Height, Recline, etc.
A - Built Material, Color, Make & Model, Brand, Price, etc.

You:
B - Eat, Play, Watch Netflix, Sleep, etc.
A - Height, Weight, Age, DOB, Name, SSN, etc.

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

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

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हठयोगी...
@hathyogi31

#3/thread on Angkor wat

Christianity and islam may be the largest religion of today’s world but Sanatan dharm has the largest religious monument in the world in the form of Angkor wat. It is situated in combodia and spread across over 400 acres / 1.6 km².

It was listed as a UNESCO World Heritage Site in 1992, which encouraged an international effort to save the complex.
It was originally built as a Hindu temple dedicated to the god Vishnu. In Khmer, the Cambodian language, Angkor means "city" and Wat means "temple grounds".

So Angkor Wat means "Temple City". Its original name was Vrah Vishnuloka or Parama Vishnuloka, meaning the sacred dwelling of Vishnu in Sanskrit.
But, it gradually turned into a Buddhist temple towards the end of the 12th century & is still used for worship today.

Angkor Wat was initially designed and constructed in the first half of the 12th century, during the reign of Suryavarman II, as the king’s state temple and capital city. It was built without the aid of any machinery, as there was no machinery available at that time.

Evidence for these dates comes in part from inscriptions, which are vague, but also from the architectural design and artistic style of the temple and its associated sculptures.

Another aspect is that the five central towers of Angkor Wat symbolize the peaks of Mount Meru,

WORLD OF SANATAN DHARM...
@world_sanatan

LESSER KNOWN DETAILS ABOUT THE BATTLE OF PRATAPGAD - THIS YOU ALL SHOULD READ

In the 1659 Adilshah sent Afzalkhan with the army of 75000 soldiers to destroy Chhatrapati Shivaji Maharaj with his empire. He was the main soldier, warrior and minister in Adilshahi Sultanate.

He was the Subhedar of Wai province.

He was very powerful physically. His height was 7.3 ft. due to same he was very popular as a strong man from Adilshahi Sultanate.

Whole India was not daring to fight with Adilshahi due to Afzal Khan.

Badi Begum Sahiba sent him to kill Chhatrapati Shivaji on any cost.

Voluntary he decided to destroy Chhatrapati Shivaji’s empire with him. He started his operation against Chhatrapati Shivaji from "wai". He destroyed many temples like as Tulja Bhavani Temple.

He destroyed so many villages, killed villagers to torture Chhatrapati Shivaji.

DETAILED VIEW- Running commentary

1. Chhatrapati Shivaji chose Pantaji as a lawyer to communicate with Afzal Khan. Pantaji was very sharp minded, who did his job very nicely.

2. He presented Chhatrapati Shivaji is fearing Afzal Khan and he wanted to invite him in his kingdom near Pratapgad.

3. Pantaji succeed in the communication with Afzal Khan and he brought him as per the planning of Chhatrapati Shivaji.

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Anu Satheesh
@AnuSatheesh5

Puthucode Annapoorneshwari Temple,
Palakkad, Kerala 🚩
#keralatemples
अन्नपूर्णे सदापूर्णे शङ्करप्राणवल्लभे
ज्ञानवैराग्यसिद्ध्यर्थं भिक्षां देहि च पार्वति

Temple is also called Puthukode Bhaghavathy Kshetram
Parasurama did Prathishta of Devi here. Temple is one amoung 👇

108 Durga temples
Navarathri festival is celebrated in a grant manner here. Annadanam is done daily on these days. The Idichu pizhinja payasam/ Chathachatayam is the main nivedyam in Annapoorneswari temple during Navarathri.
In the mornings, Devi Mahatmyam and Sundarakandam are

recited here daily.
Sri Godavarma Raja gifted lots of rice fields for the maintenance of the temple.
Annapoorneshwari holds Shanku and Chakra in her hands. Puthucode Annapoorneswari Temple is managed by the Naduvil Madom Devaswom.
🙏🕉🙏

$\U0001f1fa\U0001f1f8I Support Our Military & Law Enforcement\U0001f1fa\U0001f1f8$

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Oh my Goodness!!!

I might have a panic attack due to excitement!!

Read this thread to the end...I just had an epiphany and my mind is blown. Actually, more than blown. More like OBLITERATED! This is the thing! This is the thing that will blow the entire thing out of the water!

Tik Tok pic.twitter.com/8X3oMxvncP
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Has this man been concealing his true identity?

Is this man a supposed 'dead' Seal Team Six soldier?

Witness protection to be kept safe until the right moment when all will be revealed?!

Who ELSE is alive that may have faked their death/gone into witness protection?

Were "golden tickets" inside the envelopes??

Are these "golden tickets" going to lead to their ultimate undoing?

Review crumbs on the board re: 'gold'.

#SEALTeam6 Trump re-tweeted this.