Issue
While i am reading document of Kotlin, i saw that we should avoid using open
properties declared at base class:
It means that, by the time of the base class constructor execution, the properties declared or overridden in the derived class are not yet initialized. If any of those properties are used in the base class initialization logic (either directly or indirectly, through another overridden open member implementation), it may lead to incorrect behavior or a runtime failure. When designing a base class, you should therefore avoid using open members in the constructors, property initializers, and init blocks.
The document said that properties in derived class are not yet initialized when base class's constructor is called. But, how can we access derived class's properties which are not initialized, from base class constructor(I assumed that the incorrect behavior or a runtime failure
were caused by this situation)? Is it possible?
Solution
I don't know kotlin, but I'm assuming that open
is the same as virtual
in other languages. It is unsafe to call virtual members in a base class constructor because the base constructor is called before the derived constructor. If the overridden property requires that the derived class be fully initialized it can cause errors because the derived constructor has not yet been called when you are inside the base constructor. At least that is the way it works in .NET languages like C#.
Answered By - MarkPflug
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