[HD Pg 87, Sec. 3.6.2 - creating-wrapper-objects]

[OCAJO1]

Page 89 - "The valueOf methods of Byte, Short, Char, Integer, and Boolean guarantee that they will return cached objects for the same ranges given above"

Page 90 - "Integer i1 = Integer.valueOf(128);
Integer i2 = Integer.valueOf(128); //i1 and i2 may or may not refer to the same Integer instance"

Just to double check, the word guarantee does not apply here, because the value is higher than 127?

[admin]

Correct, the range is -128 to 127.

[flex567]

Can integer literal be boxed into a Byte. You don't mention that.

Code: Select all

Byte b = 1;

It is important in this question: enthuware.ocajp.i.v8.2.1418

[admin]

It explains the general concept in Section 3.6.2 Point 3

"All it means is that if you assign a primitive value to a wrapper variable, the
compiler will automatically box the primitive value into a wrapper object. "

There is only an example of Integer here. Will improve this to include examples of other types also.


Although there is an example of Byte inside the Note the above point:

Byte b3 = 127; //autoboxing

thank you!