Difference between reference creations

Question

What is the difference between
Object anObject;
Object anObject = null;

Answer 1

They are logically the same. But they are not the same.
The folliwng program does the same number of declarations twice and prints
Run time with no initalisation 579 ms
Run time with initalisation to null 2265 msYou can argue this is next to no difference, but there is a difference.
    public static void main(String[] args) {
        long start = System.currentTimeMillis();
        final int size = 500000000;
        for (int i = 0; i < size; i++) {
            Object a;
            Object b;
            Object c;
            Object d;
            Object e;
            Object f;
            Object g;
            Object h;
            Object j;
            Object k;
        long end = System.currentTimeMillis();
        System.out.println("Run time with no initalisation " + (end - start) + " ms");
        long start2 = System.currentTimeMillis();
        for (int i = 0; i < size; i++) {
            Object a = null;
            Object b = null;
            Object c = null;
            Object d = null;
            Object e = null;
            Object f = null;
            Object g = null;
            Object h = null;
            Object j = null;
            Object k = null;
        long end2 = System.currentTimeMillis();
        System.out.println("Run time with initalisation to null " + (end2 - start2) + " ms");
    }