Java通用成员类型在子类中删除了？

Question

I have a class with below member:

public  class BaseContainer {
    protected LinkedHashMap<Enum, MyClass> places;
}

And a subclass where I use the protected member :

public class NullContainer extends BaseContainer {
    public MyClass getSelectedPlace() {
        return places.values().iterator().next(); 
    }
}

And I get (In netbeans):
error: incompatible types
required : MyClass
found : Object

Why do I need to cast now? What happened with the type info? Was it erased just because of inheritance? What am I doing wrong.

Seems to be a bug in my java compiler then. Thanks all for the help.

Answer 1

So finally I think I found the answer to be a bug in jdk1.7.0_51 (which I am using). https://bugs.openjdk.java.net/browse/JDK-8061736 However there are oppinions that this is not a bug (see the end of bugreport):

The superclasses (respectively, superinterfaces) of a raw type are the erasures of the superclasses (superinterfaces) of any of its parameterized invocations. So as GenList is a raw type the return type of method getAValue is not A or String but Object. Which corresponds with javac's output.

(I really think this is rather a bug, because all taht this achieves is that now I am forced to cast every occurence of this member field in all subclasses, which just doesn't make any sense...)