Top 5 Machine Learning Algorithms for Data Science and ML Interviews

Hello guys, you may know that Machine Learning and Artificial Intelligence have become more and more important in this increasingly digital world. They are now providing a competitive edge to businesses like NetFlix's Movie recommendations. If you have just started in this field and are looking for what to learn, then I will share 5 essential Machine learning algorithms you can learn as a beginner. These necessary algorithms form the basis of most common Machine learning projects. Knowing them well will help you understand the project and model quickly and change them as per your need.

Difference between Random, ThreadLocalRandom and SecureRandom

There were used to be days when Math.random() method was the only way to generate random numbers in Java, but with the evolution of Java API, as of JDK 7, we now have 3 classes to generate Random numbers i.e. java.util.Random, ThreadLocalRandom, and SecureRandom. In this article, we will compare these three classes and learn some key differences between Random, ThreadLocalRandom, and SecureRandom in Java.

1. Java’s default Random class is expensive to initialize, but once initialized, it can be reused.
2. In multithreaded code, the ThreadLocalRandom class is preferred.
3. The SecureRandom class will show arbitrary, completely random performance. Performance tests on code using that class
must be carefully planned.

Random vs ThreadLocalRandom in Java

As the name suggests, the main difference between these two is how thread-safety is handled. The main operation is responsible for generating random number nextGaussian() of java.util.Random is synchronized. Since this method is used by all the methods which return random number, in multi-threading environment this method becomes a bottleneck.

In short, if two threads use the same random instance at the same time, one will have to wait for other to complete its operation. On the other hand, ThreadLocalRandom class uses a thread-local concept, where each thread has its own random number generator.

So in a contended environment, it's better to use ThreadLocalRandom. One more performance benefit of using this class is that it reuse an expensive-to-create object.

Difference between Random, ThreadLocalRandom, and SecureRandom in Java
As opposed to synchronization difference between ThreadLocalRandom and Random, SecureRandom is algorithmic different than Random and ThreadLocalRandom. Both Random and ThreadLocalRandom (later is sub-class of former) implements a typical pseudorandom algorithm. While these algorithms are quite sophisticated.

The difference between those classes and the SecureRandom class lies in the algorithm used. The Random class (and the ThreadLocalRandom class, via inheritance) implements a typical pseudorandom algorithm. While those algorithms are quite sophisticated, they are in the end deterministic. If the initial seed is known, it is easy to determine the exact series of numbers the engine will generate. That means hackers are able to look at series of numbers from a particular generator and (eventually) figure out what the next number will be. Although good pseudorandom number generators can emit a series of numbers that look really random (and that even fit probabilistic expectations of randomness), they are not truly random.

The SecureRandom class, on the other hand, uses a system interface to obtain random data. The way that data is generated is operating-system-specific, but in general, this

source provides data based on truly random events (such as when the mouse is moved).

This is known as entropy-based randomness and is much more secure for operations

that rely on random numbers.

Can you take training after passing OCMJEA 6 Exam (1Z0-897), Assignment(1Z0-865) and Essay (1Z0-866)?

Yes, you can take the training after passing the OCMJEA exam. Even though the training is a must to obtain the certification, You do not have to complete it before you give an exam. It is just listed as the first step to prepare well for your exam. If you have decent experience in core Java and enterprise Java, you can always complete the training when you are comfortable about it, but you must complete it to become an Oracle Certified Java Architect. In the last step of the exam, you need to submit a form containing the training detail to obtain credits for training.

5. ASP.Net Core Developer Roadmap

ASP.NET Core is a powerful framework for building modern web applications. To become a proficient ASP.NET Core developer, it's essential to have a roadmap that outlines the key skills and technologies involved in the development process. The ASP.NET Core Developer Roadmap provides a visual guide, helping developers navigate their way through the various stages of ASP.NET Core development. In this article, we will explore the ASP.NET Core Developer Roadmap, using the reference image as a guide, and discuss the important milestones along the journey to becoming an accomplished ASP.NET Core developer.

ASP.Net Core Developer Roadmap

Understanding the ASP.NET Core Developer Roadmap

The ASP.NET Core Developer Roadmap is a comprehensive illustration of the skills, concepts, and technologies that are essential for ASP.NET Core development. It provides a clear path for developers to follow, starting from the fundamentals of ASP.NET Core and progressing towards more advanced topics. By following this roadmap, developers can systematically acquire the knowledge and skills necessary to excel in ASP.NET Core development.

Key Milestones in the ASP.NET Core Developer Roadmap

Fundamentals of ASP.NET Core

The journey begins with a solid foundation in ASP.NET Core. Developers should start by mastering the basics of the framework, including understanding the MVC (Model-View-Controller) pattern, working with controllers, views, and models, and handling routing and URL patterns. It's crucial to grasp concepts like dependency injection and middleware, which are fundamental to ASP.NET Core development.

Entity Framework Core

Entity Framework Core is an essential component of ASP.NET Core for data access and ORM (Object-Relational Mapping). Developers should focus on learning Entity Framework Core, including creating database models, performing CRUD operations, and working with migrations. Understanding LINQ (Language-Integrated Query) is crucial for querying and manipulating data.

Web APIs

In the age of web services, building robust and scalable Web APIs is a vital skill for ASP.NET Core developers. Developers should explore topics such as RESTful API design principles, handling HTTP verbs, implementing authentication and authorization, and versioning APIs. Understanding serialization formats like JSON and XML is essential for building interoperable APIs.

Authentication and Authorization

Securing web applications is a top priority. Developers should delve into authentication and authorization mechanisms in ASP.NET Core. This includes understanding concepts like JWT (JSON Web Tokens), OAuth, and role-based authorization. Exploring frameworks like Identity Server and OpenID Connect can provide more advanced capabilities for authentication and single sign-on (SSO).

Front-end Development

To build modern and engaging user interfaces, developers should have a strong grasp of front-end development in ASP.NET Core. This includes working with HTML, CSS, and JavaScript, integrating client-side frameworks like Angular, React, or Vue.js, and handling AJAX requests. Understanding client-side bundling, minification, and optimization techniques will enhance the performance of ASP.NET Core applications.

Testing and Quality Assurance

Ensuring the reliability and stability of ASP.NET Core applications requires a strong testing and quality assurance strategy. Developers should explore unit testing frameworks like xUnit or NUnit, perform integration testing, and adopt practices such as test-driven development (TDD) and behavior-driven development (BDD). Understanding tools like Selenium or Cypress for automated UI testing is beneficial.

Deployment and DevOps

Deploying and managing ASP.NET Core applications efficiently is crucial. Developers should explore deployment options such as Azure App Service, Docker containers, and serverless architectures. Knowledge of DevOps practices, continuous integration and deployment (CI/CD), and infrastructure-as-code tools like Azure DevOps or GitHub Actions will streamline the development-to-production pipeline.

Real-time Communication

Real-time communication is an integral part of many modern web applications. Developers should explore real-time communication technologies in ASP.NET Core, such as SignalR. SignalR allows developers to build real-time, bi-directional communication between the server and the client. Understanding concepts like hubs, groups, and connection management will enable developers to implement real-time features like chat applications, notifications, and live updates in their ASP.NET Core projects.

Caching and Performance Optimization

To enhance the performance and scalability of ASP.NET Core applications, developers should explore caching techniques. ASP.NET Core provides various caching mechanisms, such as in-memory caching, distributed caching using Redis, or response caching. Understanding when and how to leverage caching can significantly improve the application's response times and reduce the load on the server. Developers should also explore performance profiling tools to identify performance bottlenecks and optimize critical sections of the code.

Microservices and API Gateway

As applications grow in complexity, developers should explore the concept of microservices and how to build scalable architectures using ASP.NET Core. Understanding the principles of microservices, including service decomposition, communication patterns, and containerization with technologies like Docker and Kubernetes, will allow developers to create modular and scalable systems. Additionally, exploring the concept of an API Gateway, such as Ocelot or Azure API Management, can help in centralizing and managing multiple microservices.

Security Best Practices

Building secure web applications is paramount in today's digital landscape. Developers should familiarize themselves with security best practices in ASP.NET Core. This includes implementing measures such as input validation, protection against common attacks (e.g., cross-site scripting (XSS), SQL injection), and secure handling of sensitive data. Keeping up with security updates, using secure authentication mechanisms, and employing HTTPS for secure communication are essential aspects of building secure ASP.NET Core applications.

Continuous Learning and Community Engagement

To excel as an ASP.NET Core developer, continuous learning and community engagement are vital. Developers should stay up-to-date with the latest advancements in ASP.NET Core, explore new features introduced in each release, and embrace emerging trends in web development. Engaging with the ASP.NET Core community through forums, user groups, and online discussions enables knowledge sharing, collaboration, and access to valuable resources. Additionally, contributing to open-source projects and attending conferences or meetups provides opportunities to learn from industry experts and expand professional networks.

Conclusion

The ASP.NET Core Developer Roadmap serves as a valuable guide for developers aspiring to become proficient in ASP.NET Core development. By following the roadmap and progressing through the outlined milestones, developers gain the necessary skills and knowledge to build robust, scalable, and secure web applications using ASP.NET Core. From mastering the fundamentals to exploring advanced concepts such as real-time communication, microservices, and security best practices, developers can leverage ASP.NET Core's capabilities to create cutting-edge web solutions.

Embrace the ASP.NET Core Developer Roadmap, utilize the reference image as a visual guide, and embark on your journey to becoming a skilled ASP.NET Core developer. With dedication, continuous learning, and active community engagement, you can stay at the forefront of ASP.NET Core development and contribute to the ever-evolving world of web development. Let the roadmap be your compass as you navigate the path to success in ASP.NET Core development.

java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver

This error comes when you try to connect to Microsoft SQL Server using Microsoft's official JDBC driver bundled in sqljdbc4.jar, but the driver class is not available in Classpath. In order to make a JDBC connection, the first step is to load the class which implements JDBC Driver interface, com.microsoft.sqlserver.jdbc.SQLServerDriver is the class which does that for MSSQL. This class is bundled in sqljdbc4.jar and if this JAR is not present in Classpath then ClassLoader is not able to locate it and throws "java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver" error. How do you fix this error? just add sqljdbc4.jar or sqljdbc4.jar

Here is an example program which can cause this error

Difference between Data Science and Machine Learning

Hello guys, if you are wondering What is difference between Data Science and Machine LEarning then you are not alone, There are lot of people who think they are same but they are not. Data Science and Machine Learning, two buzzwords that seem to be thrown around a lot these days. But what do they actually mean? And more importantly, what's the difference between the two? If you're feeling a little confused, don't worry, you're not alone. In this article, we'll break down the differences between Data Science and Machine Learning in a way that's easy to understand, and most importantly, entertaining! So, sit back, relax, and let's dive into the world of Data Science and Machine Learning.

How to Prepare for AWS certified Security Specialty Exam

Hello guys, if you are preparing for AWS Certified Security Specialty exam then you have come to the right place. Earlier, I have shared best AWS Security specialist courses and my thoughts and courses on cracking AWS Solution architect exam and today, I will share how you can prepare for AWS Security certification in depth. The AWS Certified Security Specialty" certification is one of the most esteemed credentials in the industry. There is now an official designation for data analysts on their resumes and applications. Two of today's most hotly debated topics, cloud computing, and security, come together with the AWS Security Specialty certification. If you're in the security field, bringing your skills to the cloud is a natural next step in your career development.

How to Prepare for Google Collaboration Engineer Exam? Tips and Resources

Just before 2 months , I've cleared the Google Collaboration Engineer Exam, and now working as a cloud solutions engineer. Throughout my journey of Google Collaboration Engineer Exam preparation, the greatest challenge was the lack of materials and sources. I found it hard to find out the materials for this exam. I'm here to list out some important materials which I found helpful in clearing this Google Collaboration Engineer Exam.

Best Cyber Monday Deals for Programmers

Hello Guys, I wanted to post this article a couple of days before but just couldn't manage to do it. Cyber Monday is almost over but there are still a couple of great deals for programmers who are running, particularly from PluaralSight and Udemy, two of the best online learning places. If you want to invest some money in your learning and upgrade this is the best time to do so because prices have come down drastically.

Here are the two of such deals which I have also taken advantage to renew my subscription and add some good courses on my existing collection.

1. Save up to $150 on PluralSight

I wanted to let you know about a pretty sweet deal that PluralSight is running right now.

For the first time ever, they've knocked down the price on their PluralSight Premium plan by $150.

The Premium plan includes the entire PluralSight course library, plus their new certification practice exams, interactive courses, and practice projects to help reinforce what you're learning.

This new plan adds a lot of value—and with this promotion—at a great price too.

They've also knocked $100 off their regular annual plan.

Every serious developer must have a PluralSight subscription. It's like the Netflix for Software developers.

=> Click here to save up to $150 on PluralSight

All the best with your learning

2.

10 Example of String in Java

1. String IndexOf Example
2. String SubString Example
3. String Matches Example
4. String Length Example
5. String Empty Check Example

How to replace characters in String

How to remove whitespace from String in Java

How to find length of String in Java

How to check if String is Empty in Java

How to create SubString from String in Java

How to Split String in Java

How to check if String contais a word

How to

arraylist string example in java

java object string example

java string split example

java string to inputstream example

java string to int example

java string length example

java string to double example

java switch string example

10 points about synchronized in Java

1. Synchronized can only be applied to methods and code block, you can not make a variable, a class or an interface synchronized in Java.

2. When a thread enters a synchronized block or method, it acquire lock on the object method has been called. Similarly when thread exits the block, both normally or abruptly due to any error, it relinquish the lock.

3. Synchronized keyword not only provide mutual exclusion, but also provides visibility guarantee. Memory barriers are updated when thread enter or exits synchronized block or method.

10 points about Exception in Java

1. There are two kinds of exception in Java, checked and unchecked exception. Any exception, which is subclass of java.lang.Exception but not inherited from java.lang.RuntimeException is known as checked Exception. On the other hand those inherited from RuntimeException are called unchecked exception.

2. Checked exceptions follow special symanatic rules in Java, they are literally checked by compiler during compile time.

3. All Exception are inherited from Throwable class.

4. Though Error are not inherited from RuntimeException they are also unchecked.

Why Constructor Injection is better than Setter Injection

There is no doubt that dependency injection is good, and offer several benefits. When it comes to inject dependency, there are two main ways, by using constructor and by using setter methods.

Constructor injection makes dependencies obvious
enforces order of initialization
makes wiring easy
supports testable code
more readable
enforce completeness

CreditCardProcessor ccp = new CreditCardProcessor();

OfflineQueue oq = new OfflineQueue()

Database db = new Database();

IS-A vs HAS-A Relationship Example in Java

IS-A means two classes are part of same inheritance hierarchy, while HAS-A means two classes are not part of same inheritance hierarchy but class A is composed using class B and uses it to provide certain functionality.

Java Interface and Abstract class Interview Questions

---------------------------------------
What is Abstract class?
What is interface?
Difference between Abstract class and inteface?
Can we make a class abstract without abstract method?
Can we make a class final and abstract?
Can we declare constructor in abstract class in Java?
Can an interface extend more than one interface in Java?
Can a class extend more than one class in Java?

Can we have non abstract method inside interface?
What is default method of Java 8?

Difference between SOAP and REST Style Web Service in Java

SOAP and REST are two ways to create web services in Java world, here are couple of key differences between REST and SOAP in Java

10 points about JPA Entity Class for Hibernate Java developers.

JPA Entity class is in core of JPA specification and its one of the most important thing a Java developer should know, while working with JPA implementations like Hibernate. Many Java programmers either not aware of these rules and best practices or doesn't pay enough attention while creating JPA entity class to end up with same mistakes e.g. equals and hashcode not working, issues with access type etc. This motivates me to hund down and write these rules

The entity class must have a no-arg constructor. It may have other constructors as well. The no-arg constructor must be public or protected.
The entity class must a be top-level class. An enum or interface must not not be designated as an entity.
The entity class must not be final. No methods or persistent instance variables of the entity class may be final.
If an entity instance is to be passed by value as a detached object (e.g., through a remote interface), the entity class must implement the Serializable interface.
Both abstract and concrete classes can be entities. Entities may extend non-entity classes as well as entity classes, and non-entity classes may extend entity classes.

http://stackoverflow.com/questions/6033905/create-the-perfect-jpa-entity

Further Learning
Introduction To Hibernate
Spring with JPA and Hibernate
Introduction to Spring MVC
Java Web Fundamentals by Kevin Jones

XML Interview questions and answers for programmer

XML Interview questions and answers for programmer
---------------------------------------------------
What is XML ?
Difference between DTD and XML Schema?
What is Xpath ?
What is XSLT?
What is element and attribute in XML?
What is meaning of well formed XML ?
What is benefit of using XML ?
What is XML namespace? Why it's important?
Difference between DOM and SAX parser ?
What is a CDATA section in XML?
What is SOAP and how does it relate to XML?
What is XML data Binding ?

What is XML binding ? How to you bind XML document into Java objects?
What is XML Parsing? Which XML parsers have you used ?
What is difference between DOM and SAX parsers?
What is XPATH ? Can you run XPATh expression in Java ? How?
Does Java supports XSLT? How will you do XSLT transformation in Java?
How to write xsl stylesheet to remove an attribute from xml document?
Which Java open source library have you used for XML processing?
What is xml beans? have you used it?
Which packages are related to XML functionalities in Java?
What is difference between DTD and Schema?
What are xml namespaces? how do you resolve conflicts?
What are the issues you faced while doing XML processing in Java?

XPath Example in Java

10 Example of XPATH
------------------------
package test;

import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

/**
* Simple Java program to execute XPATH expression and retrieve value from XML documents
*/
public class XPathExample {

public static void main(String[] args){
try {
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true);

DocumentBuilder builder = domFactory.newDocumentBuilder();
Document doc = builder.parse("Books.xml");

XPath xpath = XPathFactory.newInstance().newXPath();

XPathExpression expr = xpath.compile("bookstore/book[@category='COOKING']/title/text() | bookstore/book[@category='WEB']/title/text()");

Object result = expr.evaluate(doc, XPathConstants.NODESET);

NodeList nodes = (NodeList) result;
System.out.println("Result: " + nodes);
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}

}catch (XPathExpressionException ex) {
ex.printStackTrace();
} catch (SAXException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
} catch (ParserConfigurationException ex) {
ex.printStackTrace();
}
}
}

That's all about how to use XPath in Java.

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