class D {
public static void main(String args[]) {
Integer b2=128;
Integer b3=128;
System.out.println(b2==b3);
}
}
I wrote the following as this problem isn't just specific to Integer. My conclusion is that more often than not if you use the API incorrectly, you sill see incorrect behavior. Use it correctly and you should see the correct behavior:
public static void main (String[] args) {
Byte b1=127;
Byte b2=127;
Short s1=127; //incorrect should use Byte
Short s2=127; //incorrect should use Byte
Short s3=128;
Short s4=128;
Integer i1=127; //incorrect should use Byte
Integer i2=127; //incorrect should use Byte
Integer i3=128;
Integer i4=128;
Integer i5=32767; //incorrect should use Short
Integer i6=32767; //incorrect should use Short
Long l1=127L; //incorrect should use Byte
Long l2=127L; //incorrect should use Byte
Long l3=13267L; //incorrect should use Short
Long l4=32767L; //incorrect should use Short
Long l5=2147483647L; //incorrect should use Integer
Long l6=2147483647L; //incorrect should use Integer
Long l7=2147483648L;
Long l8=2147483648L;
System.out.print(b1==b2); //true (incorrect) Used API correctly
System.out.print(s1==s2); //true (incorrect) Used API incorrectly
System.out.print(i1==i2); //true (incorrect) Used API incorrectly
System.out.print(l1==l2); //true (incorrect) Used API incorrectly
System.out.print(s3==s4); //false (correct) Used API correctly
System.out.print(i3==i4); //false (correct) Used API correctly
System.out.print(i5==i6); //false (correct) Used API correctly
System.out.print(l3==l4); //false (correct) Used API correctly
System.out.print(l7==l8); //false (correct) Used API correctly
System.out.print(l5==l6); //false (correct) Used API incorrectly
}