teleren/devto huggingface dataset:
Multithreading in Java
Published: 2023-05-03 09:33:00

Multithreading is an essential technique in software development that enables programs to run multiple threads simultaneously. Java provides built-in support for multithreading, making it easy to develop multithreaded applications. In this article, we will explore multithreading in Java, including how to create and manage threads, how to synchronize threads, and how to avoid common issues such as race conditions and deadlocks.

## Creating Threads in Java

In Java, threads can be created by either extending the Thread class or implementing the Runnable interface. Here is an example of creating a thread by extending the Thread class:

```java
    class MyThread extends Thread {
        public void run() {
            // code to be executed in this thread
        }
    }
    
    // Create and start the thread
    MyThread thread = new MyThread();
    thread.start();
```

Here is an example of creating a thread by implementing the Runnable interface:

```java
    class MyRunnable implements Runnable {
        public void run() {
            // code to be executed in this thread
        }
    }
    
    // Create a thread and pass the Runnable object to it
    Thread thread = new Thread(new MyRunnable());
    thread.start();
```

## Synchronizing Threads in Java

In multithreaded applications, it is common for multiple threads to access shared resources, such as variables or objects. To prevent race conditions and other issues, Java provides several synchronization mechanisms, such as locks and semaphores.

Here is an example of using a synchronized block to protect a shared resource:

```java
    class MyCounter {
    
        private int count = 0;
          
        public void increment() {
            synchronized(this) {
                count++;
            }
        }
    
        public int getCount() {
            synchronized(this) {
                return count;
            }
        }
    }
```

In this example, the increment and getCount methods are synchronized using the this object as the lock. This ensures that only one thread can access the count variable at a time.

## Avoiding Deadlocks in Java

Deadlocks occur when two or more threads are blocked, waiting for each other to release a lock. To avoid deadlocks, it is essential to follow best practices when designing multithreaded applications. Some common best practices include:

* Avoiding nested locks

* Acquiring locks in a fixed order

* Using timeouts when acquiring locks

* Limiting the scope of locks

## Conclusion

Multithreading is a powerful technique for improving the performance of an application. In Java, multithreading is easy to implement using the built-in thread support. However, it is important to follow best practices when designing multithreaded applications to avoid issues such as race conditions and deadlocks. With careful design and management, developers can create robust and efficient multithreaded applications that deliver superior performance.
Mẹo đeo thắt lưng đúng cách chuẩn đẹp không thể bỏ qua
Tags: betl
Published: 2023-05-03 10:01:24

Thắt lưng là một trong những phụ kiện không thể thiếu trong cuộc sống hàng ngày. Việc [đeo thắt lưng đúng cách](https://1102style.vn/deo-that-lung-dung-cach/) không chỉ tạo được ấn tượng tốt với người xung quanh mà còn giúp bạn cảm thấy tự tin và thoải mái hơn trong bộ đồ mình đang mặc. Tuy nhiên, không phải ai cũng biết cách lựa chọn và sử dụng thắt lưng đúng chuẩn để tăng thêm vẻ đẹp và giá trị của bộ trang phục. Vì vậy, hãy cùng 1102 STYLE tìm hiểu các bí quyết và lưu ý khi đeo thắt lưng khiến bạn trở thành một người có gu hơn nhé.
Hướng dẫn đeo thắt lưng nam đúng cách cho mọi trang phục
Đeo thắt lưng đúng cách với quần tây
Thực tế, mỗi loại thắt lưng sẽ có kích thước phù hợp với các loại quần khác nhau. Bạn không nên sử dụng một chiếc thắt lưng cho cả quần tây, jeans, kaki. Thay vào đó, hãy kết hợp quần tây với những mẫu thắt lưng bản rộng khóa kẹp hoặc trượt.
Ngược lại, khi mong muốn theo đuổi phong cách thời trang thanh lịch nhưng vẫn đầy tự do thì bạn nên cân nhắc sử dụng sản phẩm có khóa cài bản rộng như thắt lưng Salvatore Ferragamo để tạo cảm giác thoải mái, phóng khoáng.
 Cách đeo dây nịt đúng chuẩn với giày
Nguyên tắc đeo thắt lưng đúng cách cơ bản nhất là sử dụng giày và dây đeo cùng tông màu với nhau. Theo đó, hai Item này nên có điểm tương đồng cả về chất liệu lẫn màu sắc để tạo nên hiệu ứng tuyệt vời, an toàn trong mọi cuộc họp, buổi tiệc.
Thế nhưng, bạn cũng cần lưu ý rằng cách Mix Match này đôi khi sẽ gây nên cảm giác khá nhàm chán, không có tính đột phá. Vì thế có thể cân nhắc thường xuyên thay đổi cách phối đồ để có thể đạt được các hiệu ứng mới mẻ hơn.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/w38s74w5p11y45zenk41.png)


Nguồn: https://1102style.vn/deo-that-lung-dung-cach/ 
Name: 1102 STYLE 
Hotline/Zalo: 0978531102 
Website: www.1102style.vn 
Email: 1102styleluxury@gmail.com 
Địa chỉ: 131 Văn Cao – Ngô Quyền – Hải Phòng
Xem thêm: 
https://www.instapaper.com/read/1602479676
:root isn't global
Tags: css, webdev
Published: 2023-05-03 09:50:47

Most developers prefer to keep all their CSS custom properties in one place, and a pattern that has emerged in recent years is to put those on `:root`, a pseudo-element that targets the topmost element in your document (so that's always `<html>` on web pages). But just because they're in one place and in the topmost element, it doesn't mean they're global.

I first encountered this issue with `::backdrop`: [Backdrop doesn't inherit from anywhere](https://kilianvalkhof.com/2023/css-html/backdrop-doesnt-inherit-from-anywhere/) but after a recent rendering engine update to [Polypane](https://polypane.app) I noticed that all my custom selection colors (also powered by CSS custom properties) [suddenly stopped working](https://twitter.com/kilianvalkhof/status/1649056013495205903). 

Turns out, `::selection` is also not supposed to inherit styles, and Chromium 111+ is running an experiment to see what effect changing that has. Polypane runs with experimental features turned on, and so my selection styles became broken.

This is going to catch a lot of people off-guard because I, like many others, expect CSS Custom properties defined on `:root` to just be available everywhere. I guess I would also expect `::selection` and `::backdrop` to inherit from their "parent" element to allow more dynamic styling, but the spec writes apparently don't want this.

## So if `:root` isn't global, what is? 

Well, the jury's still out. 

Discussions are happening in this GitHub issue: [Custom properties on :root](https://github.com/w3c/csswg-drafts/issues/6641) with a few options being discussed:

- Use @property with an initial value (not cross-browser supported yet, only uses the initial value).
- Make `:root` special.
- Create a new `:document` pseudo-element that does propagate custom properties.
- Create an new at-rule called `@global`, `@root` or `@document`  that you could define custom properties in.
- Make `::selection` etc inherit from their originating element (e.g. "their parent").

That last item would solve both the problems people run into (it not inheriting, and it potentially inheriting directly from `:root` so you can't overwrite custom properties in the cascade). I hope spec writers choose to do this regardless. 

Specifically, I want/expect this to work:

```css
p {
    --selection-bg: #0f0;
    &::selection {
        background: var(--selection-bg);
    }
}
```

When it comes to "a place to store global variables" I have no strong opinion, though I think it's interesting to keep in mind that in JavaScript there is now `window`, `global` and `globalThis` because the naming across contexts didn't work. 

In that light, `:document` or `@document` seem potentially problematic. For that reason, I like `@global` or `:global` (I haven't actually seen global as a pseudo-element suggested yet, but it seems to be closest to how people expect things to work now). 

In the mean time, you can use the suggestion I made in my `::backdrop` post and replace `:root` with `:root ::backdrop ::selection`. Sorry about that.
Using Numpy histogram2d
Tags: python, datascience, programming
Published: 2023-05-03 09:45:50

Histogram2d is a Numpy function used in group two by two matrix based on certain bin conditions.


For Example

```
a=np.array([0.00, 1.00, 1.00, 0.98, 0.04, 0.85, 1.00, 1.00, 1.00, 0.36, 1.00,
       1.00, 1.00, 0.00, 0.63, 1.00, 0.00, 0.15, 1.00])

b=np.array([0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1])


bins=np.array([0,0.5,1])

```

BINS : means from 0 - 0.4 is 0 and 0.5 to 1 is one 


```

cm = np.histogram2d(a,b), bins=bins)[0]

array([[5.00, 1.00],
       [1.00, 12.00]])

```
Think Like a Hacker: The Ultimate Guide for Sysadmins to Safeguard Against Cyber Threats
Published: 2023-05-03 09:32:12


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ly732t8wjj6uz7ri3rd5.jpeg)


As a sysadmin, the responsibility of safeguarding your organization's digital assets against cyber threats lies on your shoulders. In today's interconnected world, hackers are constantly looking for vulnerabilities to exploit, and it's your job to think like them to stay one step ahead.


So, how do you think like a hacker? First, understand the motivations behind their attacks. 
Whether it's financial gain, political activism, or simply a desire to cause chaos, knowing what drives hackers can help you identify potential targets and vulnerabilities.

Next, familiarize yourself with the common techniques and tools used by hackers, such as phishing, malware, and social engineering. This knowledge will help you recognize and prevent attacks before they can cause any harm.

It's also important to keep your systems up-to-date with the latest security patches and software updates. Outdated software can create vulnerabilities that hackers can exploit. Implementing strong password policies and multi-factor authentication can also go a long way in preventing unauthorized access to your systems.

Finally, establish a culture of security within your organization. Educate your employees about the importance of cybersecurity and the risks associated with careless behavior. Regularly conduct security audits and drills to identify any weaknesses in your systems and processes.

**

## conclusion
**
In conclusion, thinking like a hacker is an essential skill for any sysadmin looking to safeguard their organization against cyber threats. By understanding the motivations, techniques, and tools used by hackers, staying up-to-date with security patches and software updates, and promoting a culture of security within your organization, you can significantly reduce the risk of a successful cyber attack. Remember, the best defense is a proactive offense.
Azure Functions Tips: change the limit for the size of body in a function
Tags: azure, serverless, azurefunctions
Published: 2023-05-03 09:31:00

When you implement an Http Trigger Function that manages a request with a body, you have a size limit for the body itself. The default value for this limit is 100Mb (actually 104857600 bytes and you can read it in the [Http Trigger documentation](https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-http-webhook-trigger?tabs=python-v2%2Cin-process%2Cfunctionsv2&pivots=programming-language-csharp#limits)).

You can manage this limit using the Function App configuration. In particular, you can add the setting `FUNCTIONS_REQUEST_BODY_SIZE_LIMIT` to set the maximum number of bytes you support in a single Http request.

Just to test how this setting works, use the following simple function:

```csharp
[FunctionName("PostSomething")]
public IActionResult PostSomething(
    [HttpTrigger(AuthorizationLevel.Function, "post", Route = "post")] HttpRequest req,
    ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    return new OkResult();
}
```

You can do it also in your machine:

- Add the config to your local setting file of the Function project:

```json
{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet",
    "FUNCTIONS_REQUEST_BODY_SIZE_LIMIT": 100
  }
}
```

- Run the project:

![The log of the function runtime](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ymfeqqk3ygwgpoj9bm9e.png)

- Make a POST Http request (for example using `curl`):

```bash
curl -X POST http://localhost:7077/api/post --data "This is the payload of the request and its size is more than 100 bytes. The function should throw an exception!!"
```

- The function's log should display the error related to the size of the body:

![The Request Body Too Large error throws by the function](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/dav6tceqt1x84h5bct7h.png)

You can have the same behavior if you set the application setting value in a Function App on Azure:

![The application settings of the Azure Function](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/yhtbl9z0a9h5whu25mrq.png)

and then you can test the function:

![The test UI of the Azure Portal for an Azure Function](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/c635lgbot07ufc97pxmq.png)

having the error:

![The "request body too large" error in the Azure Function monitor page](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/kg5cd1n2alwdzwjnyv9x.png)
ai to rewrite text
Published: 2023-05-03 09:25:01

A programme that can automatically rewrite text is known as an [AI to rewrite text](https://seotoolsystem.com/ai-paragraph-rewriter-online). The tool rewrites the original material (such as an article) using its own words after using Artificial Intelligence (AI) to comprehend the original text's meaning. AI rewriters can produce updated versions of already published materials or wholly original content.
Kubernetes - Merging kubeconfig Files
Tags: kubernetes, devops, opensource
Published: 2023-05-03 09:13:21

> In this short article, we will look how we can merge a new kubeconfig file to an existing config file

## Introduction

* Kubernetes is an open-source container orchestration tool to manage containerized applications
    
* An important component of Kubernetes is kubeconfig, a configuration file used to connect to our clusters
    
* A kubeconfig file contains the cluster name and endpoint, user credentials and the context
    

## Steps

* Make a copy of your existing kubeconfig file
    

```bash
$ cp ~/.kube/config ~/.kube/config.bak
```

* Merge the old and new kubeconfig files using the below command
    

```bash
$ KUBECONFIG=~/.kube/config:~/new-kubeconfig.yml \
             kubectl config view --flatten > ~/merged-kubeconfig.yml
```

* Replace your old config with new merged config file
    

```bash
$ cp ~/merged-kubeconfig.yml ~/.kube/config
```

* List the contexts, now you can see our new cluster
    

```bash
$ kubectl config get-contexts
```

## Reference

[https://jacobtomlinson.dev/posts/2019/how-to-merge-kubernetes-kubectl-config-files/](https://jacobtomlinson.dev/posts/2019/how-to-merge-kubernetes-kubectl-config-files/)
Common topics and questions you may encounter during a React.js interview
Tags: webdev, javascript, beginners, react
Published: 2023-05-03 08:47:49

1. - React.js basics: You should have a good understanding of the React.js framework, including components, props, state, and the virtual DOM.
2. - JavaScript fundamentals: React.js is built on top of JavaScript, so it's important to have a solid understanding of JavaScript fundamentals such as variable scoping, closures, and asynchronous programming.
3. - CSS and HTML: Understanding the basics of HTML and CSS will be helpful when working with React.js, particularly when styling components.
4. - Redux: Redux is a popular state management library used with React.js. You may be asked about the basics of Redux, including actions, reducers, and the store.
5. - React Router: React Router is a library that allows you to handle routing in a React.js application. Be familiar with how React Router works and how to set up routes.
6. - Hooks: React.js Hooks are a way to use state and other React features without writing a class. You should know the basic Hooks, such as useState and useEffect.
7. - Best practices: You may be asked about best practices when working with React.js, such as code organization, performance optimization, and accessibility.
How to monitor changes in JavaScript?
Tags: javascript, webdev, tutorial, beginners
Published: 2023-05-03 08:40:24

For monitoring the changes that have been made to the DOM tree you can use MutationObserver.
MutationObserver is a built-in object that observes a DOM element and fires a callback when it detects a change. It provides the ability to watch for changes being made to the DOM tree and is designed as a replacement for the older Mutation Events feature.

###### Some common use cases for MutationObserver include:
- Augmenting third-party libraries that modify the DOM in some way but you want to extend this further or capture something from it.
- Reacting to changes in the DOM, such as when elements are created or when property changes occur.

To use MutationObserver, you first create an observer with a callback-function and then attach it to a DOM node. The config object specifies what kind of changes to react on, such as changes in the direct children of the node, changes in all descendants of the node, changes in attributes of the node, etc.

###### Here is an example adapted from MDN:
```
const targetNode = document.getElementById("some-id");
const config = { attributes: true, childList: true, subtree: true };

// Callback function to execute when mutations are observed
const callback = (mutationList, observer) => {
  for (const mutation of mutationList) {
    if (mutation.type === "childList") {
      console.log("A child node has been added or removed.");
    } else if (mutation.type === "attributes") {
      console.log(`The ${mutation.attributeName} attribute was modified.`);
    }
  }
};

const observer = new MutationObserver(callback);
observer.observe(targetNode, config);

// Later, you can stop observing
observer.disconnect();
```
###### Follow me on [Github](https://github.com/billalsiddiqi) &  [Twitter](https://twitter.com/Siddiqi47)
Liskov Substitution Principle
Tags: programming, oop, csharp, dotnet
Published: 2023-05-03 08:29:49

The Liskov Substitution Principle (LSP) states that:

> _Subtypes should be substitutable for their base types. This means that any instance of a subtype should be able to be used in place of its base type without affecting the correctness of the program._

In other words, if class _S_ is a subclass of class _T_, then an object of class _T_ should be able to be replaced with an object of class _S_ without affecting the program's properties.

## Violation of the principle

Consider the following example:

```csharp
public class FlyingAnimal
{
    public virtual void Fly()
    {
        Console.WriteLine("I am a flying animal");
    }
}

public class Penguin : FlyingAnimal
{
    public override void Fly()
    {
        throw new NotSupportedException("Penguins cannot fly");
    }
}
```

In this example, the `Penguin` class inherits from the `FlyingAnimal` class. However, since penguins cannot fly, the `Fly` method in the `Penguin` class throws an exception. This violates the LSP, as replacing an object of the `FlyingAnimal` class with an object of the `Penguin` class could cause runtime errors.

## Application of the principle

To resolve the violation of the LSP, we can use the following design:

```csharp
public abstract class Animal
{
    public virtual void Behavior()
    {
        Console.WriteLine("I am an animal");
    }
}

public class FlyingAnimal : Animal
{
    public override void Behavior()
    {
        base.Behavior();
        Console.WriteLine("and I can fly");
    }
}

public class Penguin : Animal
{
    public override void Behavior()
    {
        base.Behavior();
        Console.WriteLine("but I cannot fly");
    }
}
```

In this example, we have introduced an abstract class `Animal` and two derived classes: `FlyingAnimal` and `Penguin`. The `Animal` class has a `Behavior` method that describes the basic properties of an animal. The derived classes extend the `Behavior` method to describe additional specific properties for each type of animal. In this way, we can replace an object of the `Animal` class with an object of its subclasses without affecting the program's properties.

## Conclusion

In this article, we have discussed the Liskov Substitution Principle, which teaches us to develop derived classes that can seamlessly replace their base classes without compromising the correctness of the program. This is achieved by using proper inheritance hierarchies and polymorphism, ensuring that derived classes adhere to the contracts set by their base classes. Consequently, this principal aids in creating code that is more maintainable and extensible, as it minimizes unexpected behavior when using derived classes in place of their base classes.

## References

- [Clean Code: A Handbook of Agile Software Craftsmanship](https://www.pearson.com/en-us/subject-catalog/p/clean-code-a-handbook-of-agile-software-craftsmanship/P200000009044/9780132350884)
- [Adaptive Code: Agile coding with design patterns and SOLID principles](https://www.microsoftpressstore.com/store/adaptive-code-agile-coding-with-design-patterns-and-9781509302581)
Technical Debt. What is it? and how to avoid it.
Published: 2023-05-03 08:15:58

1/ Hey everyone, let's talk about technical debt! 💻📉

2/ For those who don't know, technical debt is like borrowing money from your future self - except instead of money, it's code that you'll have to pay back later. 😬

3/ It happens when you take shortcuts or rush through coding projects, leaving behind poorly written code that will cause headaches down the line. #technicaldebt

4/ But fear not, my friends! There are ways to avoid technical debt and save yourself from a future migraine. Here are some tips:

5/ First, take your time and plan your code carefully. Like a chef preparing a meal, make sure you have all the ingredients and steps mapped out before you start cooking. 🍳

6/ Second, don't be afraid to ask for help. Whether it's from a coworker or a Google search, there's no shame in seeking out guidance when you need it. #teamwork

7/ Third, document your code as you go, this is quite important. Think of it like leaving a trail of breadcrumbs for your future self to follow. 🍞

8/ Fourth, take care of your code by regularly updating and maintaining it. Like a car, it needs routine checkups and tune-ups to stay in good shape. 🚗💨

9/ And finally, remember that technical debt is a normal part of the coding process, and even the best programmers in the world fall victim to it. So don't beat yourself up over it, just learn from your mistakes and keep moving forward. #nevergiveup

10/ So there you have it, folks! I would like to know your take on technical debt and how you handle it. Happy coding! 👨‍💻👩‍💻
See Learning Coding as Learning Music
Published: 2023-05-03 08:14:31


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/kyx8nx7lohkgi70n7jns.jpeg)

Learning to code should be like learning music. In order to be very good in it, you MUST practice.

Just as you have fun practicing music 🎶, you should see fun in coding.

Stressful truly, but solving problem is fun. Coding is the tool.

#HTML #CSS #java #javascript #react #AI