About an issue where any object in Java is cast to an interface type

Any object in Java is strongly converted to an interface type without compiling errors

 Public class Implements eatable{    publicstaticvoid  main (String args[]) {        = (drinkable) New Apple ();    }} Interface eatable{} Interface drinkable{}

Classes in Java can implement interfaces much more, and the Java compiler cannot tell if the class implements the interface so there are no compile errors.

But a class in Java is strongly moved to another class, and if the class is not its parent, the compilation error is reported because the classes in Java are single-inherited and can be judged by the compiler.

 Public class extends eatable{    publicstaticvoid  main (String args[]) {        ( drinkable) New   Apple ();  Error inconvertible Types:can not cast Apple to drinkable    }}class  eatable{}class
     drinkable{}

About an issue where any object in Java is cast to an interface type