Variables in Kotlin, differences with Java: 'var' vs. 'val'?

user_6803201 0
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I am trying to learn Kotlin. What is val, var and internal in Kotlin compared to Java?

In Java:

 RadioGroup radioGroup;
 RadioButton button;
 Button submit;

After converting it shows:

 internal var radioGroup: RadioGroup
 internal var button: RadioButton
 internal var submit: Button
kotlin android java
4 Answers

val use to declare final variable. Characteristics of val variables

  1. Must be initialized
  2. value can not be changed or reassign

enter image description here

var is as a general variable

  1. We can initialize later by using lateinit modifier

    [lateinit also use for global variable we can not use it for local variable]

  2. value can be changed or reassign but not in global scope

enter image description here

val in kotlin is like final keyword in java

user_46957810

In kotlin we can declare variable in two types: val and var. val cannot be reassigned, it works as a final variable.

val x = 2
x=3 // cannot be reassigned

On the other side, var can be reassigned it is mutable 

var x = 2
x=3 // can be reassigned
user_79743160
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