Why should we cast to the same type?

Question

can anyone explain why am i getting incompatible type error and should cast to Object[] if ref[0] is already object array( class [Ljava.lang.Object; )

public class Test {
    public static void main(String args[]) {
        Object[] ref = new Object[1];
        Object[] x = new Object[]{1};
        while (true) {
            ref[0] = new Object[]{ref};
            System.out.println(ref[0].getClass()); //class [Ljava.lang.Object;
            ref = ref[0]; // incompatible type error
        }

    }
}

Answer 1

At compile stage, ref[0] 's data type is Object , ref 's data type is Object[] .

Object and Object[] are not the same type.