Nullable vs. Non-nullable Types
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What is Nullable vs. Non-nullable Types?
In Kotlin, the type system distinguishes between variables that can hold null values (nullable types) and those that cannot (non-nullable types). By default, variables are declared as non-nullable, meaning they must always contain a value. To allow a variable to hold a null value, you must explicitly declare it as nullable by adding a question mark (?) after the type. This distinction helps prevent NullPointerExceptions, a common source of errors in many programming languages.
Free resources to learn Nullable vs. Non-nullable Types
More in stage 26: Visibility Modifiers
Nullable vs. Non-nullable Types: common questions
Can I learn Nullable vs. Non-nullable Types in Hindi?
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Is this Nullable vs. Non-nullable Types tutorial for beginners?
It is lesson 79 of 153 in the free Kotlin roadmap, in stage 26, Visibility Modifiers. If you are new to Kotlin, start from stage 1 and come back here in order; if you already know the earlier stages, this lesson stands on its own.