Smart Cast

23 Jun 2024 . kotlin .

In Java, there is a requirement of explicit type casting on the variable before accessing the properties of that variable.

Object ob = "GeeksforGeeks";
 
if(ob instanceof String) {
    // Explicit type casting
    String str = (String) ob;
 
    System.out.println("length of String " + str.length());
 }

In Kotlin, no need to explicitly cast something that was already checked.

val str1: String? = "GeeksforGeeks"
    
if(str1 is String) { //already checked
        
   // No Explicit type Casting needed.
   println("length of String ${str1.length}")
}