Slides to a talk I gave on-stage at TechieAid about Kotlin vs Java. Date: August 1st, 2018 My website: https://bapspatil.com

1. Kotlin vs Java
Bapusaheb Patil
Google Certified Android Developer &
OpenClassrooms Android Mentor
www.bapspatil.com
TechieAid

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What’s Kotlin?

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Kotlin is a new
programming
language…
...that’s gonna replace
Java.

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Hold on, what’s
wrong with Java?

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● Requires more code
to do simple tasks.
● NullPointerExceptions
make life hell.
● Not that friendly with
Android.

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Enter,
Kotlin.
● Takes care of
null-safety.
● More concise &
much shorter code.
● Runs on JVM.
● Can be used along
with Java files.
...and more that can’t be covered in my talk.

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Basic Data Types
● Double
● Float
● Long
● Int
● Short
● Byte
● Boolean
● Char
● String
● Array

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Declaring A
Variable...
● var - Mutable variable
● val - Immutable or final variable
Example:
var name: String? = “TechieAid”
val students: Int = 120
? means the variable can be null.

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Null-Safety
// Doesn’t compile, to be safe.
var name: String = null
// Compiles safely
var name: String? = null

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Java
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View view) {
Toast.makeText(getApplicationContext(),
“Hey there!”, Toast.LENGTH_SHORT).show();
}
}
Kotlin
button.onClick { toast(“Hey there!”) }

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Java
public class User {
private int id;
private String name;
public User() { }
public User(String name, int id) {
this.id = id;
this.name = name;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public String toString() {
return “User: “ + “ID=” + this.id
+ “Name=” + this.name;
}
}
Kotlin
data class User (
val id: Int,
val name: String
)
And that’s another
reason Kotlin rules!

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Fun Facts About Kotlin?

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Android Documentation is
now in Kotlin too!

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Number of Android Apps in Kotlin
Stats from Jetbrains.com
2018 2019

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Number of Android Apps in Kotlin

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Great! Where Do I Learn Kotlin From?
Kotlinlang.org • Official Website & Documentation
Google Codelabs •
Kotlin Is Awesome! • kotlin.link
Mindorks.com •
Talking Kotlin •
Kotlin Bootcamp for Programmers •

17. Thank you.
Questions?
Get in touch with me:
Website • www.bapspatil.com
Email • hi@bapspatil.com
TechieAid