Insertion sort is similar to the way people sort playing cards: given some cards that are sorted and a new card to be added, make a hole where the new card should go and put the new card into the hole.
public static void insertionSort( Integer[] a ) {
for ( int i = 1; i < a.length; i++ )
{ int hole;
Integer item = a[i];
for ( hole = i;
hole > 0 &&
item.compareTo( a[hole - 1] ) < 0;
hole-- )
a[hole] = a[hole - 1];
a[hole] = item; } }