Upcasting a method method return type from a generic type is a common use case in Java where you can use the return type you just created to do more than what needs to be done. For example, if you have a method named getName that returns the name of the person, you can upcast it to the PersonGenericType and get the method as the return type.
Upcasting is one of those things where it’s not such a big deal. You can just cast a variable to a new type, but doing so in a generic method causes you to lose information about the type of the variable, because the compiler can’t know which specific implementation that variable will run in. As a result, you end up with a method that doesn’t get passed in any parameters, and the type of the variable is completely wrong.
This is a very common mistake that can happen when people try to upcast an object to another type. It makes no sense because the compiler cant know which specific implementation that variable will run in, and it can result in a method called by the wrong type.
The upcast type that i’m talking about is the type of a variable that is in the same class and has the same name. This is called by the compiler as “upcasting” a variable to another type.
This mistake is pretty easy to fix. If you don’t know how to fix it, don’t do it. The type of the variable is completely wrong. The correct type of the variable is a super class of the type of the variable. This is how the compiler knows that the variable is in the same class and has the same name as a super class.
The thing that happens when you compile a program with upcasting is that the compiler will attempt to upcast the variable to the super class of the type of the variable. But a super class is a super class of anything that is a class. So there is no variable that is not a super class of something. So it means your variable is not upcasting to a super class and therefore is not the correct type.
This is one of those situations where using the right variable type can be as important as knowing the right type of variable. Sometimes the compiler will try to cast a variable of a type that it doesn’t understand. When you run upcasting an object to a superclass of an object, there is no way to know which is correct. However, you can always check it yourself. In Java, you can use the classname operator.
There is always a superclass object. If you are casting to a superclass, you can avoid casting to a sub-class. This is called upcasting. In reality, there is no need to cast anywhere. Upcasting is simply a way to tell the compiler that you are casting to a class that you dont understand.
Upcasting is a way to tell the compiler that you are casting to a superclass that you dont understand. For example, suppose you have two objects, Employee and EmployeeOf. The first line of code would say, “Cast Employee to EmployeeOf”. However, the compiler will say that EmployeeOf is not an object, so it needs to be cast back to Employee.
Downcasting on the other hand, is exactly what it sounds like. A downcast is when the compiler says the object is of type EmployeeOf, but the class you are casting to is Employee. The compiler will tell you that there are no other classes that have the same name, so just cast to Employee.