shruti-basil-hs

public class Car {

    private String make;
    private String model;
    private String registration;

    public String getmake() {
        return make;
    }

shruti-basil-hs

//**Attempting to assign null to a regular variable**

var hello: String = "hello"
hello = null // compilation error


//**Null safety** 

//By checking for Null
val b = "kotlin"

shruti-basil-hs

//* let 
fun <T, R> T.let(f: (T) -> R): R = f(this)

//Scoping
Person.getName().let { name ->
  print(name)
}
// name is no longer visible here

//To check for null values

shruti-basil-hs

data class Car(val make: String, val model: String, val registration: String)

shruti-basil-hs

static class Person {
   String name;
}

public void printName(Person person) {
   if (person.name != null) {
       foo(person.name.length());
   }
}

shruti-basil-hs

class Person(var name: String?) // the name property can be null
class Person(var name: String) // the name property cannot be null

shruti-basil-hs

fun <T, R> T.let(f: (T) -> R): R = f(this)

shruti-basil-hs

Person.getName().let { name ->
  print(name)
}
// name is no longer visible here

shruti-basil-hs

fun <T> T.apply(f: T.() -> Unit): T { f(); return this }

shruti-basil-hs

Person(name).apply { foo() };

//Equivalent 4 line Java code
Person getFoo(String name) {
  Person person = new Person(name);
  person.foo();
  return person;
}