public static void main(String[] args) {
Integer a = 128;
Integer b = 128;
System.out.println(a == b);
System.out.println(a.equals(b));
System.out.println(a.toString());
System.out.println(a);
System.out.println(a.hashCode()); Integer c = 1;
Integer d = 1;
System.out.println(c == d);
System.out.println(c.equals(d));
System.out.println(c.toString());
System.out.println(c);
System.out.println(c.hashCode());
}
Integer a = 128;
Integer b = 128;
System.out.println(a == b);
System.out.println(a.equals(b));
System.out.println(a.toString());
System.out.println(a);
System.out.println(a.hashCode()); Integer c = 1;
Integer d = 1;
System.out.println(c == d);
System.out.println(c.equals(d));
System.out.println(c.toString());
System.out.println(c);
System.out.println(c.hashCode());
}
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() {}
} public static Integer valueOf(int i) {
if (i >= IntegerCache.low && i <= IntegerCache.high)
return IntegerCache.cache[i + (-IntegerCache.low)];
return new Integer(i);
}