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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 practicals.
https://t.co/VFImq1o2uW
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
4. Packages and Access Modifiers (2 days)

- Default package, Normal package and its use case
- Various access modifiers and how they behave in different types of packages.
- Write a few programs to practice

https://t.co/kCrMArRhmC
5. Conditional Statements and Loops (2 days)

- While/Do While
- For loops
- If/else conditions
- Switch case
6. Objects, Classes & Interface (4 days)

- Objects
- Abstract Class/Concrete Class
- Constructors, Methods
- Interface
- What is Inheritance through classes and interfaces
- Method Overloading/Overriding
- static, final keywords
7. Basics of Multithreading (2 days)

- What is threads, How do create them.
- Thread class, hierarchy
- Learn to create simple threads using Thread class and using Runnable.
- Various methods of Thread class
- Write some program to practice

https://t.co/C7JfpMCgdV
8. Exception Handling (3 days)

- Problem solved by Exception Handling
- Exception Hierarchy
- Checked/Unchecked Exception
- How to create custom exception
- throw, throws, throwable, try-catch, finally
9. Collections (5 days)

- Basics of Collections
- Classes/Interface with its hierarchy in Collection framework.
- All about List, Set & Map, their differences, internal data structures and internal working.
- Collections util class
10. Lambda & Streams (3 days)

- What are lambda functions & why is it introduced
- Functional Interface and Functional Programming
- Write programs to practice
- Streams API and its methods.
- Stream pipelines and their methods

https://t.co/XqJlbBdpb6
Tips:

1. Skip these Topics:
- Advance Multithreading Concepts
- Swing/Applet
- Java. util package
- Java. io package

2. Prepare a daily plan, and spent 5-8 hrs daily to achieve this goal.

3. Don't fall into tutorial hell, write programs at every stage.
Conclusion:

Don't hardwire that these are the only topics you should know in Core Java, the rest is garbage.

No. That's not true!

But as an absolute beginner, you should at least know this much while the rest of the topics you will discover as and when you need.

More from Vikas Rajput

Vikas Rajput
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:
GETTERSANDSETTERS
Vikas Rajput
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.
CREATIONOBJECTJAVA
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Vikas Rajput
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.
OOPS
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.
ACCESS MODIFIERS
Vikas Rajput
Vikas Rajput
@vikasrajputin
Ultimate Backend Development Roadmap in 2022:

📂Basics
📄Internet
📄Client-Server Architecture
📂Any Language & Framework
📄Java + Spring
📄Python + Django
📄JS + Node
📂Git
📂SQL/NoSQL
📂Basic DevOps
📄CI/CD, Cloud Hosting (AWS, etc)
📄Docker, Kubernetes
ALL

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So friends here is the thread on the recommended pathway for new entrants in the stock market.

Here I will share what I believe are essentials for anybody who is interested in stock markets and the resources to learn them, its from my experience and by no means exhaustive..

First the very basic : The Dow theory, Everybody must have basic understanding of it and must learn to observe High Highs, Higher Lows, Lower Highs and Lowers lows on charts and their

Even those who are more inclined towards fundamental side can also benefit from Dow theory, as it can hint start & end of Bull/Bear runs thereby indication entry and exits.


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Anu Satheesh 🇮🇳...
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Thuravoor Narasimha Swamy Temple
Alappuzha, Kerala
#KeralaTemples 🚩

Thuravoor Narasimha Swamy or Thuravoor Mahakshetram is situated in Alappuzha with Narasimha Swamy and Sudharshana Moorthy as main Prathishta.
Temple has separate Sannidhi for Vadakkanappan ( Narasimha) and 👇


Tekkanappan ( Sudarshana).

Sthala puranam says that Vigraham of Narasimha was brought from Varanasi. Swami Padmapadar, shishya of Adi Sankaracharya, had worshipped the same Vigraham at Kashi.
A Namboodiri, on his way to Kashi saw a powerful light which disappeared here 👇


Namboodiri dug the place and he found a beautiful beautiful Vigraham made of Anjanasila. It is said that the vigraham occupied a site, which was the place of Durga Devi
Sudarshana Moorthy is about 6 Ft, Chaturbahu. Deepavali is famous festival here.
Om Narasimha Swamine Namah
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WHO ARE VALAKHILYAS?

Valakhilyas are 60000 Rishis who are thumb-sized. They were born to Kratu and Kriya. Rig Veda says that they sprang from the hairs of Brahma.
They move in front of Surya dev’s chariot as Sun moves daily and
shine like brilliant lights due to severe tapasya.


Tamil literature says that the main task of Valakhilyas is to prevent human beings from being scorched. They absorb the excess heat from the sun by travelling in front of him. They, in turn, get energy from Skanda and Ma Durga. The food of Valakhilyas is only wind.
@SriRamya21


Once, Rishi Kashyap performed a yagna and invited all the Devas and Rishis to help him. Indra brought a whole mountain of trees for firewood. The Valakhilyas were hardly able to lift anything but leaves. Even when they were moving leaves, they fell into rain water puddles.


Indra made fun of them. So they cursed Indra saying that his slayer would be born as the son of Kashyapa. When Indra apologized, they modified the curse that the son shall be initially an enemy of Indra, but later will become his friend.


This son born later to Kashyapa was Garuda. He flew to Indraloka to get Amrita and defeated Indra.
Later, he restored amrit vessel to Indra and was honoured as the King of birds and as the mount of Sri Vishnu.
@JumbuTweeple @artist_rama
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श्रीमाली हितेश अवस्थी...
@HiteshAwasthi89
Sri Maha Bhairavar Rudhra alayam, Chengalpet, Tamilnadu

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with Rudrakshas on both the sides of the entrance This temple has a circular Sanctum Sanctorum which has twelve stepseach representing a sign of zodiac and after that twelve steps we find the supreme deity of this temple Sri Kshetra Paata Bhairava. 2/n


Beneath the Bhairava, in the lower level are installed the Ashta Bhairavas, SapthaRishis in the form of stones, and Saptha Kannis in the form of brass lamps. Thereare a number of little blue and white lights in the ceiling that is shaped like a dome.. 3/n


which give an ethereal atmosphere when switched on. The steps representthe twelve signs of the zodiac and when one steps over them to reach thesanctum sanctorum all the doshas pertaining to the horoscope are cleared onceand for all..4/n


The Sthala Vriksham ”Peepal Tree” which is grown on a pedestal, a trident which is considered as Bhairavi, Pancha Mukha Anjaneya, Prathyankara Devi, Subramanya, Rudra Vinayaga, Vaishnavi Devi, Naga Rudra, Eswara, Vana Durga etc. 5/5

#IncredibleBharat
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1. Let's talk about Albanians. No, not THOSE Albanians, in the Balkans. The Caucasian Albanians, the pre-Turkish inhabitants of the land now known as Azerbaijan. 🇦🇿


2. Yeah, I know, there's also an "Iberia" there, which should cause even more confusion (with Spain), but let's focus on "Albania".

3. This ancient church in the village of Nij (or Nic), just south of the Caucasus Mountains, belongs to the Udi people, a Christian minority in Azerbaijan descended from the area’s pre-Turkic Caucasian Albanians. 🇦🇿


4. Nearby are the ruins of the Caucasian Albanian capital of “old” Gabala (Qebele), where I was given a personal tour by one of the resident archeologists (just for showing up). 🇦🇿


5. Only a very tiny portion of the extensive site has been excavated. “Every place you dig,” the archeologist told me, “you will find artifacts.” This whole field is a city waiting to be uncovered.
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