How to reverse all the data values in an Array

public class ReverseArrayValuesGeneric {

	static int indexVal=0;
	static String when[] = {"Before","After"};

	//Generic method to process the reverse logic in an Array of values
	private static <E> void reverseArrayData(E[] numArray) {

		// Calculate the rear Index position in an array based on the length
		int startIdx = 0, rearIdx = numArray.length - 1;

		/*
		 * Start swapping the data at first and last positions of an array, do continue
		 * swapping data by increasing first index to the next higher index, and by
		 * decreasing last index to next lower index, until those positions cross each
		 * or have same value
		 */

		while (startIdx <= rearIdx) {
			E tempNum = numArray[startIdx];
			numArray[startIdx] = numArray[rearIdx];
			numArray[rearIdx] = tempNum;
			startIdx += 1;
			rearIdx -= 1;
		}
	}

	// Generic method to display an array values in some specific format
	private static <E> void dispArray(E[] numArray) {

		String dataType=numArray.getClass().getSimpleName().replace("[]", "s");
		System.out.println("An Array of "+dataType+" - "+when[indexVal]+" reversing");
		System.out.print("[ ");
		for (int i = 0; i < numArray.length; i++) {
			System.out.print(numArray[i] + " ");
		}
		System.out.println("]");
		indexVal ^=1;
	}

	public static void main(String[] args) {

		// Initialized an Array to Integer values
		Integer[] numArray = { 21, 98, 42, 59, 79, 65, 32 };
		dispArray(numArray);
		reverseArrayData(numArray);
		dispArray(numArray);
		System.out.println();

		// Initialized an Array to Float values
		Float[] floatArray = { 12.0f, 89.0f, 24.0f, 95.0f, 97.0f, 56.0f, 23.0f };
		dispArray(floatArray);
		reverseArrayData(floatArray);
		dispArray(floatArray);
		System.out.println();

		// Initialized an  Array to Double values
		Double[] doubleArray = { 21.0, 98.0, 42.0, 59.0, 79.0, 65.0, 32.0 };
		dispArray(doubleArray);
		reverseArrayData(doubleArray);
		dispArray(doubleArray);
		System.out.println();

		// Initialized an Array to Characters
		Character[] charArray = { 'G', 'I', 'L', 'K', 'N', 'A' };
		dispArray(charArray);
		reverseArrayData(charArray);
		dispArray(charArray);
		System.out.println();

		// Initialized an array to Strings
		String[] strArray = { "JOHN", "DAVE", "RUSS", "MIKE", "SANJAY" };
		dispArray(strArray);
		reverseArrayData(strArray);
		dispArray(strArray);
	}
}