MergeSort and Quick Sort

package mergeSort;

import java.util.Random;

/**
* Array are rearranged with smallest item first
* @author
*
*/
public class MergeSort {
private static final int NUM_ITEMS = 30;
private static final Random rnd = new Random();

public static void main(String[] args) {
Integer[] a = new Integer[NUM_ITEMS];

for(int i=0; i>
void insertionSort(T[] array, int left, int right){
for(int p= left+1; p<= right; p++){
T tmp = array[p];
int j;
for(j=p; j>left && tmp.compareTo(array[j-1])<0; j--){
array[j] = array[j-1];
array[j] = tmp;
}
}
}

public static >
void mergeSort(T[] a){
@SuppressWarnings("unchecked")
T[] tmpArray = (T[]) new Comparable[a.length];

mergeSort(a, tmpArray, 0, a.length-1);
}

/**
* Internal method that makes recursive calls
* @param a an array of Comparable items
* @param tmpArray an array to place the merged result
* @param left the left-most index of the subarray
* @param right the right-most index of the subarray
*/

private static >
void mergeSort(T[] a, T[] tmpArray, int left, int right){
if(left < right){
int center = (left + right)/2;
mergeSort(a, tmpArray, left, center);
mergeSort(a, tmpArray, center+1, right);
merge(a, tmpArray, left, center+1, right);
}
}

/**
* Internal method that merges two sorted halves of a subarray
* @param a
* @param tmpArray an array to place the merged result
* @param leftPos
* @param rightPos the index of the start of the second half
* @param rightEnd
*/
private static >
void merge(T[] a, T[] tmpArray, int leftPos, int rightPos, int rightEnd){
int leftEnd = rightPos - 1;
int tmpPos = leftPos;
int numEles = rightEnd - leftPos + 1;

//Merge
while(leftPos <= leftEnd && rightPos <= rightEnd){
if(a[leftPos].compareTo(a[rightPos])<=0){
tmpArray[tmpPos++] = a[leftPos++];
}else{
tmpArray[tmpPos++] = a[rightPos++];
}
}

//copy rest of first half
while(leftPos <= leftEnd){
tmpArray[tmpPos++] = a[leftPos++];
}

//copy rest of right half
while(rightPos <= rightEnd){
tmpArray[tmpPos++] = a[rightPos++];
}

//copy tmpArray back
for(int i=0; i=0; index--){
//swap(rnd.nextInt(index+1), index);
int rndPos = rnd.nextInt(index+1);

int tmp = array[rndPos];
array[rndPos]= array[index];
array[index] = tmp;
}
}

}

import util.SortUtil;

public class QuickSort {

public static void main(String[] args) {
int[] a = new int[30];

for(int i=0; i=0; index--){
//swap(rnd.nextInt(index+1), index);
int rndPos = rnd.nextInt(index+1);

int tmp = array[rndPos];
array[rndPos]= array[index];
array[index] = tmp;
}
}

}