Check out example codes for "kotlin vs java". It will help you in understanding the concepts better.

Code Example 1

setBackground(Color.cyan);   // sets predefined color cyan to background of frame

Code Example 2

JavaScript can be used to do neat things like creating 
animation in HTML. ... JavaScript code is run on a 
browser only, while Java creates applications that run 
in a virtual machine or browser. Java is an OOP 
(object-oriented programming) language, and JavaScript is
specifically an OOP scripting language.

Code Example 3

Java is an object-oriented programming language. ... Kotlin is a new programming language, which handles some modern features. Kotlin is also a statically typed programming language. Kotlin is a good choice for developing server-side applications, allows users to write concise and expressive code.

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