I do not have a java compiler and I would like to check how treats java the comparison of Integer Objects with primitives. Can someone confirm that the results of the following comparisons are correct:
Integer a = 500;
long b = 500;
a == b //-> false
a.equals(b) //-> true
Is it generally true that in the first type of comparison java does Boxing and in the second Unboxing and compares primitive values?
See my results
Integer a = 500;
long b = 500;
System.out.println(a == b);
System.out.println(a.equals(b));
output
true
false
this is because the first comparison uses unboxing
b == a.intValue()
which produces true, because in Java 500L == 500 is true.
The second comparison uses boxing
a.equals(Long.valueOf(b))
this produces false because a and b are instances of different classes. See Integer.equals impl:
public boolean equals(Object obj) {
if (obj instanceof Integer) {
return value == ((Integer)obj).intValue();
}
return false;
}
