Convert byte array to long using shifting and ByteArray and compare the performance

ByteBufferVersusShifting.java

package main;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;

/**
 * The objective is to compute the value of long represented as a sequence of
 * bytes using ByteBuffer and by shifting, and compare the performance.
 * 
 */
public class ByteBufferVersusShifting {

	public static long usingByteBuffer(ByteBuffer byteBuffer) {
		return byteBuffer.getLong(0);
	}

	public static long usingShifting(byte[] bytes, int offset) {
		long retVal = 0;
		retVal |= ((long) bytes[offset + 7] & 0xFF);
		retVal <<= 8;
		retVal |= ((long) bytes[offset + 6] & 0xFF);
		retVal <<= 8;
		retVal |= ((long) bytes[offset + 5] & 0xFF);
		retVal <<= 8;
		retVal |= ((long) bytes[offset + 4] & 0xFF);
		retVal <<= 8;
		retVal |= ((long) bytes[offset + 3] & 0xFF);
		retVal <<= 8;
		retVal |= ((long) bytes[offset + 2] & 0xFF);
		retVal <<= 8;
		retVal |= ((long) bytes[offset + 1] & 0xFF);
		retVal <<= 8;
		retVal |= ((long) bytes[offset] & 0xFF);
		return retVal;
	}

	public static long timeIt(Runnable r) throws Exception {
		long start = System.nanoTime();
		r.run();
		long end = System.nanoTime();
		return (end - start);
	}

	public static void main(String[] args) throws Exception {
		final byte[] bytes = new byte[] { 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x00 };
		final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
		byteBuffer.order(ByteOrder.LITTLE_ENDIAN);

		final long niterIncrement = 10000000;

		// Warm up
		for (long i = 0; i < 100000; i++) {
			usingShifting(bytes, 0);
		}
		for (long i = 0; i < 100000; i++) {
			usingByteBuffer(byteBuffer);
		}

		for (int j = 1; j <= 20; j++) {
			final long niter = niterIncrement*j;
			
			long shiftingTime = timeIt(new Runnable() {

				@Override
				public void run() {
					for (long i = 0; i < niter; i++) {
						usingShifting(bytes, 0);
					}
				}

			});

			long byteBufferTime = timeIt(new Runnable() {

				@Override
				public void run() {
					for (long i = 0; i < niter; i++) {
						usingByteBuffer(byteBuffer);
					}
				}

			});
			
			System.out.printf("%12d, %12d, %12d, %.2f\n", niter, shiftingTime, byteBufferTime, (double)byteBufferTime/(double)shiftingTime);
		}
	}
}