Java怀旧：About left/right shift, negative value representation and signextended(while shifting)

package com.super119;

public class NegativeShift {

    public static void main(String[] args) {
        byte b = -8;
        /*
         * Be caution:
         * 1. byte will be auto promoted to int while shifting
         * 2. left shift has not sign-extended
         *    right shift has sign-extended but it has ">>>" to remove sign-extended
         * 3. negative value represented in "two complement" way
         */
        // sign-extended, so we got "-4" here.
        System.out.println(b + " >> 1 is: " + (b >> 1));
        // we got "-16" here.
        System.out.println(b + " << 1 is: " + (b << 1));
        // sign-extended canceled, so we got "2147483644" here.
        System.out.println(b + " >>> 1 is: " + (b >>> 1));
        
        int i = -0x7FFFFFFF; // represents as "1000...1" in memory
        // left shift has not sign-extended
        System.out.println(i + " << 1 is: " + (i << 1)); // so we got a 2 here
        // The reason for why left shift has not a "<<<" operator is,  
        // it will exceed the max value of int
    }
}