Widening Reference Conversion

Question

5.1.4 Widening Reference Conversions
From any array type to type Cloneable.
From any array type to type java.io.Serializable
Why does the following code fail when trying to convert array as mentioned above?
     String[] arr1 = new String[] { "hello", "world" };
     SomeClass myCloneable = (SomeClass) (arr1);
class SomeClass implements Serializable, Cloneable {
Cannot cast from String[] to SomeClassMessage was edited by:
jp_in_chains

Answer 1

You can think of the inheritance tree like this:
          Serializable
Class       String[]When casting, you can only go up the tree, never down
it. Since Serializable is above String[], you could
cast String[] to Serializable, like this:
Serializable srsly =
(Serializable)someStringArray;
You can go both up and down, but going up one branch and then down the other will give a ClassCastException at runtime