public static Integer valueOf(int i) {

        if(i >= -128 && i <= IntegerCache.high)

            return IntegerCache.cache[i + 128];

        else

            return new Integer(i);

    }

private static class IntegerCache {

        static final int high;

        static final Integer cache[];

        static {

            final int low = -128;

            // high value may be configured by property

            int h = 127;

            if (integerCacheHighPropValue != null) {

                // Use Long.decode here to avoid invoking methods that

                // require Integer's autoboxing cache to be initialized

                int i = Long.decode(integerCacheHighPropValue).intValue();

                i = Math.max(i, 127);

                // Maximum array size is Integer.MAX_VALUE

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

            }

            high = h;

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

            int j = low;

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

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

        }

        private IntegerCache() {}

    }

// value of java.lang.Integer.IntegerCache.high property (obtained during VM init)

    private static String integerCacheHighPropValue;

    static void getAndRemoveCacheProperties() {

        if (!sun.misc.VM.isBooted()) {

            Properties props = System.getProperties();

            integerCacheHighPropValue =

                (String)props.remove("java.lang.Integer.IntegerCache.high");

            if (integerCacheHighPropValue != null)

                System.setProperties(props);  // remove from system props

        }

    }

package test1;

public class Demo1 {

    public static void main(String[] args) {

        System.out.println(Integer.valueOf(200)==Integer.valueOf(200));

    }

}

false