Java, Shifting Elements in an Array

Logically it does not work and you should reverse your loop:

for (int i = position-1; i >= 0; i--) {                
    array[i+1] = array[i];
}

Alternatively you can use

System.arraycopy(array, 0, array, 1, position);

Assuming your array is {10,20,30,40,50,60,70,80,90,100}

What your loop does is:

Iteration 1: array[1] = array[0]; {10,10,30,40,50,60,70,80,90,100}

Iteration 2: array[2] = array[1]; {10,10,10,40,50,60,70,80,90,100}

What you should be doing is

Object temp = pool[position];

for (int i = (position - 1); i >= 0; i--) {                
    array[i+1] = array[i];
}

array[0] = temp;