Scale Mode and Window Mode Changes in Ubuntu

If we are not able to see the Menu bar on Ubuntu then it is confirmed that we are in Scale Mode. 

we can switch to Window Mode by clicking Right Ctrl and C 

How do implicit work in Spark/Scala

Scala has a way to add methods to existing classes, like extension method in Kotlin (and C# as I remember), but does it in a different way, through implicits.

To add the method to existing class, you first create implicit class:

object StringImplicits {
  implicit class StringUtils(s: String) {
    def someCoolMethod = println("Yooo")
  }
}

object Application extends App {
    import StringImplicits._
    val s = "Hello"
    s.someCoolMethod
}

You import this StringUtils and can call someCoolMethod on instance of String

Notice that StringUtils class takes String as a constuctor param.

When calling some method on String, scala compiler first looks this method in String class.

If it does not find it, it will look imported implicit classes which take String param.

If found, it calls the method from that class.

If no such class found, it will raise the error.

How to Install Guest Additions (Enable Fullscreen, Shared Clipboard, Drag & Drop) on Ubuntu 18.04 LTS in VirtualBox?

Step 1: Update Package Lists sudo apt update Step 2: Upgrade Packages sudo apt upgrade Step 3: Click on 'close' button at the top right, and then click on 'Power Off the Machine'. Step 4: Click on 'ok' button. Step 5: Go to 'Settings', and then 'General'. Click on 'Advanced' tab. Step 6: Enable Bidirectional in shared clipboard, and Drag 'n' drop. After that start your ubuntu 18.04 LTS, and login. Step 7: Install Dependencies Required for Guest Additions, open terminal and run the command below:- sudo apt install build-essential dkms linux-headers-$(uname -r) Step 8: After installation of dependencies, click on 'Devices' in top menu, and then click on 'Insert Guest Additions CD Image'. After that, click on run button. Install it. Step 9: Install virtualbox-guest-dkms to enable shared clipboard and Drag and Drop Features. After that, restart ubuntu.