Kotlin Null Safety

Null check in kotlin

if(a != null)  {
//do something
}

Kotlin Null Safety

// Variable types in Kotlin don't allow the assignment of null. 
// Declare a nullable varible by adding ? at the end of its type.
var neverNull: String = "This can't be null"            
neverNull = null                                        // Error
var nullable: String? = "You can keep a null here"      
nullable = null                                         // Ok
var inferredNonNull = "The compiler assumes non-null"   
inferredNonNull = null                                  // Error
fun strLength(notNull: String): Int {                   
    return notNull.length
}
strLength(neverNull)                                    // Ok
strLength(nullable)                                     // Error

Source: play.kotlinlang.org

Similar codes

0 vote326 views1 answer
Kotlin read file line by line
Kotlin
2 votes356 views2 answers
Kotlin remove duplicates from list
Kotlin
-1 vote349 views1 answer
Kotlin time hours
Kotlin
1 vote327 views1 answer
Kotlin inheritance
Kotlin
0 vote353 views1 answer
Kotlin settextappearance alternative
Kotlin
1 vote333 views2 answers
Kotlin list map to another list
Kotlin
2 votes318 views1 answer
Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6. Please specify proper '-jvm-target' option
Kotlin
0 vote325 views1 answer
Recyclerview infinite scroll kotlin
Kotlin
0 vote355 views1 answer
Android show keyboard programmatically
Kotlin
1 vote334 views1 answer
How to create random alphanumeric in kotlin
Kotlin