program help: i want a java program to implement heap sort algorithm and merge - Help.com

public static void heapsort( Comparable [ ] a )
{
for( int i = a.length / 2; i >= 0; i– ) /* buildHeap */
percDown( a, i, a.length );
for( int i = a.length - 1; i > 0; i– )
{
swapReferences( a, 0, i ); /* deleteMax */
percDown( a, 0, i );
}
}

private static int leftChild( int i )
{
return 2 * i + 1;
}

private static void percDown( Comparable [ ] a, int i, int n )
{
int child;
Comparable tmp;

for( tmp = a[ i ]; leftChild( i ) < n; i = child )
{
child = leftChild( i );
if( child != n - 1 && a[ child ].compareTo( a[ child + 1 ] ) < 0 )
child++;
if( tmp.compareTo( a[ child ] ) < 0 )
a[ i ] = a[ child ];
else
break;
}
a[ i ] = tmp;
}

public static final void swapReferences( Object [ ] a, int index1, int index2 )
{
Object tmp = a[ index1 ];
a[ index1 ] = a[ index2 ];
a[ index2 ] = tmp;
}

I need a merge sort algorithm and Java implementatin