我遇到了一些不理解的问题。为什么下面的 for each 循环是非法的,而第二个完全相同的循环却可以?
public interface SomeInterface<T> {
List<SomeNamedObject> getObjects();
void doSomething(P1 p1, T p2);
}
public class SomeNamedObject {
private String text;
}
public class Clazz {
private SomeInterface someInterface;
...
public void someMethod() {
// Error Type mismatch: cannot convert from element type Object to TestClass.SomeNamedObject
for (SomeNamedObject someNamedObject : someInterface.getObjects()) {
// This loop won't compile as the someInterface.getObjects returns just a List and not a List<SomeNamedObject>
}
// Warning Type safety: The expression of type List needs unchecked
// conversion to conform to List<TestClass.SomeNamedObject>
List<SomeNamedObject> objects = someInterface.getObjects();
for (SomeNamedObject someNamedObject : objects) {
// This loop compiles
}
}
}