java - Inheritance with two levels of generic abstract classes -

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how code cannot launch car's implementation of doinbackground. missing something? not talking exception or crash, never executed.

here code snippet :

fourwheels.java

public abstract class fourwheels<params, progress, result> extends asynctask<params, progress, result> {     @override     protected abstract result doinbackground(params... params); }

car.java

public class car extends fourwheels<void, void, string> {     @override     protected string doinbackground(void... params)     {         string dummy = "dummy";         return dummy;         } }

mainactivity.java

car car = new car(); fourwheels fourwheels = (fourwheels)car; fourwheels.execute(); // should call doinbackground car...


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