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Given an array a[] consisting of N integers and an integer K, the task is to find the minimum cost to reduce the given array… Read More »
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In this article we will learn how to use optional in java 8 streams. Optional is a container object which may or may not contain null value. Some of the most important methods in Optionals are .
get method. The reasoning behind this method is to use proper naming of the method. More detail about this can be found here. Instead of get, orElseThrow should be used.So now lets look into the code on how to use optional in Java 8 stream. In this example we will try to see how to filter null values or provide a default value if value is not.
First we will see how to filter null values using java 8 and Java 9 Optional.
package com.jbt.core;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;
/*
* @author javabeginnerstutorial.com
*/
public class optional_java_8_stream {
public static void main(String[] args) {
List<jbt> list = new ArrayList<>();
list.add(new jbt("name1", 12));
list.add(new jbt("name2", null));
list.add(new jbt(null, 12));
String name = list.stream().map(jbt::getName)
.filter(Optional::isPresent)
.map(Optional::orElseThrow)
.collect(Collectors.joining(","));
System.out.println(name);
// Since JDK 9
name = list.stream()
.map(jbt::getName)
.flatMap(Optional::stream)
.collect(Collectors.joining(","));
System.out.println(name);
//orElse method can be used to provide default value incase there is no value present. Like in this case NO_NAME will be provided when name is null.
name = list.stream()
.map(jbt::getName)
.map(name1 -> name1.orElse("NO_NAME"))
.collect(Collectors.joining(","));
System.out.println(name);
}
}
class jbt {
private String name;
private Integer age;
public jbt(String name, Integer age) {
this.name = name;
this.age = age;
}
public Optional<String> getName() {
if (name == null) {
return Optional.empty();
}
return Optional.of(name);
}
public Optional<Integer> getAge() {
if (age == null) {
return Optional.empty();
}
return Optional.of(age);
}
}
In the present-day scenario, a majority of the companies are preferring Online Interviews for the recruitment process. Though Online Interviews are quite beneficial as it is more convenient and cost-effective for both – the recruiters & the job seekers! However, preparing for such Online Interviews is a not-so-easy job and it requires the same efforts and dedication as it would for a traditional in-person interview. But…do you know that your smartphone can help you considerably to prepare and ace your Online Interviews? Yes, you heard it right!! In today’s technologically advanced world, there are numerous mobile phone applications available that will not only help you to prepare well for the online interviews but will also make this journey more efficient and effective!!
Indeed, from creating an enriching resume to connecting with the corporate people or practicing mock interviews to comparing different companies, there are various mobile apps available for each task that can make everything is just a few clicks away. Although, as millions of applications are available over the web, to pick up the relevant and worthwhile ones for yourself can be a daunting task. No Worries, in this article, we will let you know about those 7 must-have mobile apps that can help you to prepare for Online Job Interviews:
Needless to say, if you’re preparing for an online interview (or offline as well!!) to get into the tech organization whether it be a Product-based or a Service-based or even a Startup Company, GeeksforGeeks is the must-have app for you to excel your preparation. GeeksforGeeks, founded in 2009, is a one-stop solution for all your interview learning requirements such as Programming Languages, Data Structures & Algorithms, Coding Practice Questions, Company Wise Interview Preparation, etc. Moreover, the app offers around 20,000+ Programming Questions, 40,000+ Articles, and the Interview Experiences of leading companies such as Microsoft, Facebook, Google, and many more.
Meanwhile, the app comes up with a user-friendly interface and offers you a lot of other worthwhile features such as Personalized Feed Based on your Interests, Sharing of Articles, Offline Reading, Night Mode, and various others that will help you to make your preparation process more convenient & efficient.
Glassdoor, founded in 2007, is one is of the most recommended app for the candidates who are preparing for online interviews. The app gives you all the required insights of the company such as the latest job listings, company reviews, interview experiences, and even salary reports as well. Meanwhile, you can follow your target companies to get the latest updates or information and can easily apply also for the jobs at the earliest. Also, you can know about the work environment and identify the pros and cons of a particular company through the app.
Moreover, the app has an easy-to-use interface and offers you numerous ravishing features such as it allows you to organize the jobs and content, create and manage notes, and discover relevant job profiles as per your requirements. Furthermore, you can also get several crucial interview tips and career advice to boost up your preparation.
Indeed, your resume is responsible for marketing your skills & knowledge and it makes the first impression of yours on the interviewer. Hence, you’re required to create a professional, attractive, and worthwhile resume to grab the attention of recruiters in a positive aspect. And here comes the role of CV Engineer! Yes, CV Engineer is a resume builder mobile app that helps you to create a professional resume or CV in an easier & efficient way, and that too free of cost!! The app offers you various resume templates, resume advice, etc. developed by the professionals in the industry.
The app provides numerous other beneficial features as well such as easy editing options, customizable resume fields, easy download & sharing options, and many more that can help you to build an enriching resume for your online interviews or other career opportunities.
As they said, “Practice makes a man perfect!!”. This applies here also as before proceeding to the actual online interview you’re required to gain some experience with several online mock interviews and get familiar with the interview scenario to boost up your preparation and enhance your confidence. Meanwhile, Talview – Candidate App, is a mobile application that offers you to practice your interviewing skills in a technological-advanced virtual environment to prepare yourself effectively for the actual interviews.
Moreover, the app can be used for attending an online video assessment with the employer, all it required is that employer needs to invite you to attend the assessment (or if you’re already having a QR code) and you need to enter the code to complete your assessment. Also, the app has a very user-friendly interface and easy to use functionalities that makes it the most recommended and convenient platform to practice your interview skills.
If you’re preparing for Online Interviews or looking for any other career opportunities, it becomes quite essential for you to connect with professionals of the particular industry to get some advice or useful insights & information to boost up your preparation in the right direction. And, LinkedIn is the one-stop solution for all these tasks. LinkedIn, founded in 2002, is a social networking platform that allows you to connect with the professionals & industry experts to build a worthwhile professional network. Also, you can discover various job vacancies and career opportunities on the platform in a few clicks!
Furthermore, LinkedIn also offers several other crucial features as well such as resume builder, sharing of posts with the community, latest industry news & updates, and many more that can be taken into consideration while preparing for the online interviews.
For all the students who are preparing for online interviews, Interview Questions and Answers is one of the most recommended apps. The app offers you more than 5000 job interview questions along with answers from beginner to advanced level. And apart from the general HR interview questions, the app also offers the questionnaire and respective tips for aptitude tests, personality tests, telephonic interviews, and many more. Indeed, practicing these questions will surely boost your confidence and take your preparation level for the online interview to the next level.
Moreover, the app comes up with unique functionality, content design, and attractive themes that makes it very user-friendly and easy to use. Also, the app offers the offline feature i.e, you’ve only required the internet connection for the first time to successfully load the entire data and then you can access and read it anywhere or anytime without having a net connection. What else you need?
Now, you must be thinking that how can a cloud storage platform like Dropbox can help you out in your online interview preparation, right? Maybe it won’t directly impact your interview preparation but through Dropbox, you can easily keep all your resources such as resume, notes, assignments, required documents, etc. in a single place and can access from anywhere or anytime. Hence, it will eventually make your preparation journey more convenient and efficient. The app offers you an easy to use interface to upload and transfer files to the cloud and share them with anyone as well across the globe.
Moreover, Dropbox is one of the most secure platforms and also supports the feature of accessing the files in offline mode. And yes, you can start to utilize the Dropbox functionalities with zero cost, although you can switch over to the paid version as well to use some advanced features.
So, these are several most-recommended mobile apps that can help you to prepare for your online interview. And if you still haven’t downloaded & installed these apps, just do the same as soon as possible and utilize these apps in the most productive way possible to ace your upcoming online interviews!!
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JavaScript is a multi-paradigm language that supports programming types that are event-driven, functional, and imperative (including object-oriented and prototype-based). Originally, JavaScript was only used on the client-side. Although, JavaScript is still used as a server-side programming language these days. To sum up, in a short sentence, JavaScript is the language of the web.
What is JavaScript Framework? Why use them at all?
JS frameworks are JavaScript programming libraries that have pre-written code to use for standard programming functions and tasks. It’s a framework to create websites or web applications around.
Let’s start with why do we need JavaScript frameworks? It’s perfectly possible to code without using them – but a well-chosen framework can make the work far easier. What’s more, they ‘re free and open-source, so there’s no risk in trying, now is there?
First and foremost, it will increase your productivity. Think of it as a workaround of sorts: you have to write fewer code manually because there are already pre-written and ready-to-use functions and patterns. Some components of the website do not need to be custom-made, so you can build and expand on pre-built ones. Frameworks are more adaptable for website design and most website developers prefer it. Let’s take a look at the best JS Frameworks.
The current leader in the JavaScript UI framework field is React. At first, Facebook developers started working on it to simplify their work. The application called Facebook Ads was growing extremely fast, which meant complicated management and support. As a result, the team started building a framework to help them with efficiency. They had an early prototype before 2011 and, two years later, the framework was open-source and available to the public. A lot of business giants are currently using it: AirBNB, PayPal, Netflix, etc.
React is based on a reusable component. Simply put, these are code blocks that can be classified as either classes or functions. Each component represents a specific part of a page, such as a logo, a button, or an input box. The parameters they use are called props, which stands for properties. Speaking of syntax, most developers agree that React is easy to learn when you already know JavaScript.
React uses JSX, an XML syntax that combines JavaScript and HTML. It’s not a JavaScript template; it’s full-on JavaScript. Some new developers might find JSX a bit confusing at first. After working with it for a while, however, you will understand how beneficial it is. React has a lot to do with it, and it’s a library that you should look out for if you’re in front-end web development.
Angular is one of the most powerful and open-source JavaScript frameworks. Google operates this framework and is designed to use it to develop a Single Page Application (SPA). This development framework is known primarily because it gives developers the best conditions to combine JavaScript with HTML and CSS. Over half a million websites, such as google.com, youtube.com, etc., use Angular.
One of the factors it is known to be so reliable is the support of Google. It is also the JavaScript UI framework of choice for Google app developers. Angular has a component-based structure, just like React. You can manipulate, nest, and reuse them as you need them. You will need to use TypeScript to write an application to Angular. It’s a JavaScript superset that uses the same syntax but also supports static typing and classes. In TypeScript, you get access modifiers, enums, generics, hybrid types, and more. Generally speaking, Angular is a fantastic platform to look at if you’re a new dev.
Vue is an open-source JavaScript framework for creating a creative UI. The integration with Vue in projects using other JavaScript libraries is simplified because it is designed to be adaptable. More than 36,000 websites are currently using Vue. Companies like Stackoverflow, PlayStation, etc. rely on Vue for their UI websites.
Vue.js is also quite simple to learn: you just need all the background knowledge you need is JavaScript and HTML. Another strength of Vue.js is its official command-line interface (CLI). It is basic tooling that speeds up development by offering a ton of plugins, presets, instant prototyping, and an interactive project scaffolding tool. Some of its features include components, templates, transitions, and two-way data binding, as well as a reactivity focus. Reactivity occurs when you change or update any of the JavaScript objects in Vue. Vue.js uses something called the Shadow DOM that makes the page rendering fast.
JQuery is probably the most popular JavaScript library out there with so many features for modern-day development. JQuery is a fast and concise Library of JavaScript created by John Resig in 2006. It is a cross-platform JavaScript library designed to simplify HTML client-side scripting. More than 19 million websites are currently using jQuery! Companies like WordPress, Facebook, Google, IBM, and many others rely on jQuery to provide some kind of web browsing experience.
You can use the jQuery API to handle, animate, and manipulate an event in an HTML document, also known as DOM. Also, jQuery is used with Angular and React App building tools. In short, one of the most important JavaScript libraries for web development.
It’s one of the most popular JavaScript frameworks. It can be used to create a single page application. The development of this framework involves the idea that all server-side functions must flow through an API, which would help to achieve complex functionality by writing less code.
BackboneJS is a lightweight JavaScript library that enables client-side applications running in a web browser to be developed and structured. Unlike other frameworks, Backbone puts the developer in charge of selecting the right tool that works best for a given project. More than half a million websites are currently using Backbone, including tumblr.com, espn.com, soundcloud.com, and many more.
Node.js is an open-source, server-side platform built on the Google Chrome JavaScript Engine. The number of websites using NodeJS has increased by 84,000. It is one of the most downloaded, cross-platform runtime environments for running JavaScript code. Node.js is an asynchronous, single-threaded, non-blocking I/O model that makes it lightweight and efficient. The Node.js package ecosystem, npm, is also the largest open-source library ecosystem in the world.
Ember.js is an open-source JavaScript framework that was originally released by Yehuda Katz in 2011. It was initially known as SproutCore 2.0 before it became known as Ember.js. Work on the Ember framework started in 2011 and version 1.0 was released two years later. Instead of one company supporting the project, Ember has many supporters who are usually users of the framework, such as LinkedIn and Yahoo.
It is also highly scalable and can be used for large projects. Apple Music, which has more than 60 million subscribers worldwide, was built on Ember. If you want to see how you can – there’s a tool called the Ember Inspector that allows you to take a closer look at Ember ‘s projects online.
Ember features an excellent build tool, borrowed from many other SPA frameworks, called Ember CLI. This build tool has everything you need to get started. Do you need a router? It’s built-in there. Need to be tested? It’s built-in, too. Do you need to work with back-end data? There’s data on Ember. Ember.js follows many of the same principles that Ruby has on the Rails. It’s highly thought-out, flexible, and prefers convention over configuration. Ember.js is just getting better, and I would highly recommend it to you.
A web framework called Skybreak was released by the end of 2011. In a couple of months, the team changed its name to Meteor. As of now, it’s version 1.8.1. Using plain JavaScript, you can build applications that can be used across multiple platforms, including but not limited to Android and iOS. The Meteor JS framework provides full-stack solutions. The use of this framework includes important areas such as back-end development, database management, business logic, and front-end rendering.
Meteor is promoting itself as the fastest way to build JavaScript apps. It’s gaining popularity on the market with more than 13,000 websites using Meteor. Websites like mtv.com, meteofrance.com, and so on, use Meteor to build their UI.
The polymer is an open-source JavaScript library maintained by Google to build web applications using web components. It also supports both one-way and two-way data binding, thus creating a more extensive area of application. When you compare Angular to Polymer as both are built by Google, Angular is a comprehensive framework for web app development, while Polymer is only a library for web component design. It was the very first library to allow interactive building applications through the use of web components. Currently, more than 3000 websites are using polymer, to name a few there are virustotal.com, rogers.com, zeplin.io, and so on.
Aurelia is a front-end, open-source framework developed by Rob Eisenberg. Aurelia 1.0 was released for the first time in 2016. Aurelia consists of function-oriented modules, such as plugins, routing, testing, dependency injection, and many more. You can use the Aurelia JS framework to develop web, mobile, and desktop applications. The modularity also allows you to create apps of different sizes. Aurelia supports both Babel and TypeScript. It is also fully compatible with future JavaScript versions.
Out of the choices presented in this guide, Aurelia may be one of the youngest: we only got the 1.0 version in mid-2016. However, this gives it a slight edge: according to its creators, Aurelia offers a component model that best meets the best web standards. It uses a lot of newer ECMAScript features (ECMAScript helps dictate JavaScript standards) and encourages you to use these new features to write your code. This is a good thing because you don’t learn a custom syntax that only works with Aurelia. Check it out if you find this interesting!
For those of you who are new to web development – you’ll hear a lot of cynical people talking about how the JavaScript world has become too fast. They ‘re going to groan that new JavaScript libraries and frameworks are coming out too quickly and that everyone is trying to do the same thing. They ‘re not wrong that it’s fast-paced, but that shouldn’t stop you from going out and learning about these JavaScript frameworks and libraries. I’ve only given you a taste of each of them. It’s up to you to pick up and start learning.
Don’t try to do it all at once, though: pick a framework and get it perfect. You don’t need to learn all of them. You just need to learn at least one thing, so you can get your foot in the door somewhere.
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Angular has finally released its latest version, Angular 9, on 7th February 2020. This release is a major update of angular, which switches application that adds the new and improved Ivy compiler and runtime by default, faster testing, better debugging, and many more improvements.
Versions 4x, 5x and 6x are no longer supported. However, Angular 7x supported till the 18th of April 2020 whereas version 8x will have support until 20th November 2020.
First, update to the latest version of 8
In a nutshell these are the new features of Angular 9:
IVy is enabled by default means if you want to fall back to view engine, we have to opt-out of IVy.The angular compatibility compiler will upgrade view engine-compatible libraries to Ivy when installed in an Ivy application project
For instance:
// tsconfig.json
{
"angularCompilerOptions": {
"enableIvy": false
}
} // polyfills.ts
// Only used in multilingual Ivy applications
// import '@angular/localize/init';
The new version of Angular 9 supports binding CSS properties as part of the IVY styling rewrite:
[style.color] = "myColor" [style] = "{color: myOtherColor}"
myDirective & gt;
@Component({
host: {
style: "color:blue"
},
…
})…
@Directive({
host: {
style: "color:black",
"[style.color]": "property"
},
…
})
…Angular 9 introduces ways to debug the code or components in the development mode, esteem techniques, and tools to develop is application are:
Angular 9 introduces three modes for checking the expression and binding within the template of your application and can report any types of errors it finds:
The expostulated versioned files option in the service worker assist group config has been removed. Thus, ngsw-config.json file will look like
"assetGroups": [{"name": "test", "resources": {"files": [ "/*/.txt"]}}]The Nullish coalescing and optional chaining feature of the Typescript 3.7 helps to stay in sync with the environment. To top it all, Angular 9 will support usage of the same TypeScript Diagnostics format for the TypeScript Compiler diagnostics, which will generate a more descriptive error message.
Ivy opens a platform for developers to speed up the application by reducing the size of JavaScript bundles. Hence, it is important for Angular 9 developers to redesign and decrease the size of downloadable files, to increase the mobile user experience.
Angular 9 provides a new TestBed.inject() instead of the deprecated TestBed.get() method:
This one is mostly for library users. Your codebase will be automatically migrated after you have updated to version 9. In this version, you have to always use the generic ModuleWithProviders<T> type to show your module type. Your declaration might have been looking like this
@NgModule({
…}) export class MyModule {
static forRoot(config: SomeConfig): ModuleWithProviders {
return {
ngModule: SomeModule,
providers: [{
provide: SomeConfig,
useValue: config
}]
};
}
}
But this is how they should look now.
@NgModule({
…}) export class MyModule {
static forRoot(config: SomeConfig): ModuleWithProviders & lt;* SomeModule * & gt; {
return {
ngModule: SomeModule,
providers: [{
provide: SomeConfig,
useValue: config
}]
};
}
The Angular 9 Language Service for Visual Studio Code and WebStorm will benefit from some improvements. For example, URL definition will become more consistent. Style URLs will be checked in the same way as template URLs. Diagnostics will also be improved in the Angular Language Service. For example, TypeScriptHost will be able to differentiate severity logging by log, error, and debug methods. Plus, template URLs and style URLs that do not point to actual files will now be diagnosed as such by the Language Service.
Angular 9 will update API Extractor to the newest version. Angular uses Bazel, an open-source tool that enables building automation and software testing. Angular users can miss out as potential bugs are resolved and new features are implemented in software libraries.
AOT, along with Ivy speeds up the creation of applications. To activate AOT for your project, open the angular.json file, and set aot to true.
“options”: {
“outputPath”: “dist / project”,
“index”: “src / index.html”,
“main”: “src / main.ts”,
“polyfills”: “src / polyfills.ts”,
“tscongif”: “tsconfig.app.json”,
“aot”: true
In the end, we can understand very clearly that the new update of Angular 9 has challenged drawback factors such as large bundle files which irritated and impacted download times, application performance and User experience have been modified so you should play around with it and get into the new room of update.
Angular 9 makes it easy to use Google Maps and YouTube in your front-end apps. Angular 9 added support for TypeScript 3.7 and improved the IDE and language service extension, which will increase the productivity of Angular developers and help them spot errors when developing apps. Many bugs have been fixed, along with stability and performance issues.
The post Angular 9 features with examples appeared first on Java Beginners Tutorial.
Amazon Web Service(AWS) supports multiple popular programming languages like Java, Python, Ruby, PHP, and Node.js, etc. All the programming languages are useful in one or another way. All the programming languages have different characteristics, communities, support, and ecosystems to consider when making choice. Lets, discuss some of the popular programming languages supported by AWS
Java is an object-oriented language with fewer dependencies. It is a secure and dynamic language designed to have high performance. Java is one of the earliest languages used in business-critical ideas. It has a wide range of libraries and frameworks supported.
Java Applications in AWS Have the Following Merits:
These merits of Java help it in running a Java-based web application on various AWS services like Amazon Simple Storage Service (S3), Amazon Elastic Compute Cloud (EC2).
Python is a dynamic, high level, open-source programming language. It is relatively a newer language in the world of programming languages and in AWS environment as well. This is the simplest language and beginners friendly.
The benefits of Python in the AWS environment:
Using the SDK for Python, you can build applications on top of Amazon S3, Amazon EC2, Amazon DynamoDB, and more.
Ruby is also a popular object-oriented programming language having training available online, both for beginners, with no coding experience, and experts in the field. Ruby has a repository of reusable libraries easily maintained and deployed in the form of RubyGems.
Benefits of Ruby:
With Ruby, developers can easily deploy their applications on various AWS services like Amazon S3, Amazon EC2, DynamoDB, and more. Ruby is really a programmer’s best friend.
PHP is an open-source server-side scripting language. PHP code is executed on the server so you need a web browser to execute PHP code. Major companies including Facebook, WordPress, Twitpic, Flickr, and Imgur are part of the PHP alumni.
Features of PHP:
The PHP SDK is a modern, open-source PHP library that makes it easy to integrate your PHP application with AWS services like Amazon S3, Amazon Glacier, and Amazon DynamoDB.
Node.js is the newest entry to the list of languages supported by AWS. Node.js applications are written in JavaScript and can be run within the Node.js runtime on OS X, Microsoft Windows, and Linux. Leaders such as Yahoo and LinkedIn have implemented portions of their applications on Node.js.
Why Node.js?
The Node.js SDK helps take the complexity out of coding by providing JavaScript objects for AWS services including Amazon S3, Amazon EC2, DynamoDB, and Amazon SWF.
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