/*public static void main(String[] args) {

        Integer a = 128, b = 128;

        Integer c = 127, d = 127;

        System.out.println(a == b);//false

        System.out.println(c == d);//true

    }*/

    /*public static void main(String[] args) {

        Integer int1 = Integer.valueOf("100");

        Integer int2 = Integer.valueOf("100");

        System.out.println(int1 == int2);//true

    }*/

    public static void main(String[] args) {

        Integer int1 = Integer.valueOf("300");

        Integer int2 = Integer.valueOf("300");

        System.out.println(int1 == int2);//false

    }
    

public static Integer valueOf(String s) throws NumberFormatException {

        return Integer.valueOf(parseInt(s, 10));

    }

public static Integer valueOf(int i) {

        if (i >= IntegerCache.low && i <= IntegerCache.high)

            return IntegerCache.cache[i + (-IntegerCache.low)];

        return new Integer(i);

    }

private static class IntegerCache {

        static final int low = -128;

        static final int high;

        static final Integer cache[];

        static {

            // high value may be configured by property

            int h = 127;

            String integerCacheHighPropValue =

                sun.misc.VM.getSavedProperty("java.lang.Integer.IntegerCache.high");

            if (integerCacheHighPropValue != null) {

                try {

                    int i = parseInt(integerCacheHighPropValue);

                    i = Math.max(i, 127);

                    // Maximum array size is Integer.MAX_VALUE

                    h = Math.min(i, Integer.MAX_VALUE - (-low) -1);

                } catch( NumberFormatException nfe) {

                    // If the property cannot be parsed into an int, ignore it.

                }

            }

            high = h;

            cache = new Integer[(high - low) + 1];

            int j = low;

            for(int k = 0; k < cache.length; k++)

                cache[k] = new Integer(j++);

            // range [-128, 127] must be interned (JLS7 5.1.7)

            assert IntegerCache.high >= 127;

        }

        private IntegerCache() {}

    }