Literal array in Object[] initialization

[Ruben Soto]

I don't understand why the following results in a compiler error:

import java.util.*;
public class ObjectArray {
    public static void main(String[] args) {
        Object[] oa1 = new Object[]{"aaa", new Object(),
                                    new Vector(), 10}; // OK, 10 autoboxes
        Object[] oa2 = new Object[]{"aaa", new Object(),
                                    new Vector(), {}}; // Compiler error
    }
}

The reason why I don't understand this is that it is legal to do something like:
int[][] a = {{1, 2}, {}};
And an array is an object, so why doesn't the above work?

[Ruben Soto]

Nevermind, I think I realized why it's not legal. Arrays must have a type, and when you do:
int[][] = {{4,3,4}, {4,5,3}, {}};
the type of each of the inner array literals is unequivocally int[]. However, when you just stick a {} inside an Object[] initializer, there is no necessary type information.