UUID to BigInteger rountrip

JavaApplication1.java

package javaapplication1;

import java.math.BigInteger;
import java.util.UUID;

public class JavaApplication1 {
    
    public static void main(String[] args) {
        final UUID uuid = UUID.randomUUID();
        System.out.println("uuid=" + uuid.toString());
        
        final long msb = uuid.getMostSignificantBits();
        final long lsb = uuid.getLeastSignificantBits();
        System.out.println("msb=" + msb);
        System.out.println("lsb=" + lsb);
        
        BigInteger number = BigInteger.valueOf(msb);
        number = number.shiftLeft(64);
        number.or(BigInteger.valueOf(lsb));
        System.out.println("number=" + number);
        
        //now reverse the process to reconstruct our uuid from the big integer
        System.out.println();
        
        final long lsb2 = number.and(BigInteger.valueOf(0xFFFFFFFFFFFFFFFFl)).longValue();
        final long msb2 = number.shiftRight(64).and(BigInteger.valueOf(0xFFFFFFFFFFFFFFFFl)).longValue();
        System.out.println("msb2=" + msb);
        System.out.println("lsb2=" + lsb);
     
        final UUID uuid2 = new UUID(msb2, lsb2);
        System.out.println("uuid2=" + uuid2.toString());
    }   
}