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    • July 26, 2018 at 4:00 pm #12818
      Tom
      Participant

      I was wondering why in java constructors are not inherited? You know when you have a class like this:

      public class ABC {

      public ABC(ServiceA serviceA, ServiceB serviceB, ServiceC serviceC){
      this.serviceA = serviceA;
      //etc
      }

      }
      Later when you inherit from ABC, java will complain that there is no default constructor defined. The solution is obviously something like:

      public class XYZ extends ABC{

      public XYZ(ServiceA serviceA, ServiceB serviceB, ServiceC serviceC){
      ABC(serviceA,serviceB,serviceC);
      }

      }

      Why java doesn’t support constructor inheritance? Is there any benefit in not allowing this inheritance?

    • July 26, 2018 at 4:16 pm #12819
      John
      Participant

      In Java Constructors are not polymorphic.
      When you are dealing with already constructed class, you could be handling a declared type of the object, or any of its sub classes.
      In Java a constructor is always called on the specific type,eg new String(). A hypothetical subclasses have no role in this.

    • July 26, 2018 at 4:31 pm #12820
      Java Lover
      Participant

      You essentially do inherit the constuctors in the sense that you can simply call super if and when appropriate, it’s just that it would be error prone for reasons others have mentioned if it happened by default. The compiler can’t presume when it is appropriate and when it isn’t.

      The job of the compiler is to provide as much flexibility as possible while reducing complexity and risk of unintended side-effects.

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