Mastering High Performance with Kotlin

The lateinit modifier

The lateinit modifier allows you to declare non-nullable variables without initializing them. Let's look at the following example:

class Main {    private lateinit var name: String    fun onCreate() {        name = "Jack"        println(name)    }}

This code, when decompiled to Java, looks as follows:

public final class Main {   private String name;   public final void onCreate() {      this.name = "Jack";      String var10000 = this.name;      if (this.name == null) {         Intrinsics.throwUninitializedPropertyAccessException("name");      }      String var1 = var10000;      System.out.println(var1);   }}

Whenever you try to get a value from the name property, an additional check is invoked:

if (this.name == null) {    Intrinsics.throwUninitializedPropertyAccessException("name");}