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Vikas Rajput
@vikasrajputin 1 year, 10 months ago 171 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().

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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.

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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

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

These 5 youtube channels will teach you programming more than a CS degree

🧵👇

1. FreeCodeCamp

https://t.co/RQae8ZU2wx

2. Programming with Mosh

https://t.co/NkaUHP5Waa

3. Derek Banas

https://t.co/yIe2G1wskd

4. Traversy Media

https://t.co/LQgK4nze2g

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Thread.

Recently, Harsimrat Kaur @HarsimratBadal_ claimed in parliament that Guru Tegh Bahadur protected the religion of Hindus despite of being a Non-Hindu. And Hindus owe a huge favor to others.

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Thread on
"Intraday Banknifty Strangle based on OI data"

(System already shared, today just share few examples)
(1/n)

-Trade timing after 9:45

-Check Banknifty change in OI data at 9:45, and identify the highest OI built up in call side and put side

-We will sell both strikes with combined premium as SL on both legs.
(2/n)

28th June 2021

BN open-35440
At 9:45 trading at 35350
Highest OI in call side at 35500 CE and 35000 at put side
Strike selection 35500 CE- 35000 PE
(3/n)

29th June 2021

BN open-35323

At 9:45 trading at 35112

Highest OI in call side at 35300 CE and 35000 at put side

Strike selection 35300 CE (232) - 35000 PE (150) Combined premium 382 , Both legs SL 382
(4/n)

30th June 2021

BN open-35030

At 9:45 trading at 35002

Highest OI in call side at 35000 CE and 35000 at put side

Strike selection 35000 CE(176)- 35000 PE(213) Combined premium 389 , Both legs SL 389
(5/n)