Some utility functions for handling byte conversions.

ByteUtils.java

package com.amirkhawaja;

import java.nio.ByteBuffer;

public final class ByteUtils {

    private ByteUtils() {
    }

    public static long stringToLong(String s) {
        return ByteBuffer.wrap(s.getBytes()).getLong();
    }

    public static byte[] longToBytes(long x) {
        final ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
        buffer.putLong(0, x);
        return buffer.array();
    }

    public static long bytesToLong(byte[] bytes) {
        final ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
        buffer.put(bytes, 0, bytes.length);
        buffer.flip();//need flip
        return buffer.getLong();
    }

}