Sunday, 17 May 2020

lateinit Vs by lazy

Both "lateinit" and "by lazy" are Kotlin Property initializers.

lateinit:
  • Use it with mutable variable [var]
  • Allowed with only non-nullable data types
  • This modifier is not allowed on properties of primitive types
  • It is a promise to compiler that the value will be initialized in future.
  • If you try to access lateinit variable without initializing it then it throws UnInitializedPropertyAccessException.
by lazy:
  • Lazy initialization was designed to prevent unnecessary initialization of objects.
  • Your variable will not be initialized unless you use it.
  • It is initialized only once. Next time when you use it, you get the value from the memory.
  • It is thread safe (It initializes in the thread where it is used for the first time. Other threads use the same value stored in the cache).
  • The variable can only be val.
  • The variable can only be non-nullable.

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