Re: Updating an object in a HashMap
John W. Kennedy wrote:
Arne VajhHj wrote:
alacrite@gmail.com wrote:
On Feb 13, 6:00 pm, alacr...@gmail.com wrote:
hm.get("test1").intValue() += 5;
//Error:The left-hand side of an assignment must be
a variable
Thank you all for your replies. I did not realize that Boolean, Byte,
Short, Character, Long,
Float, and Double objects were immutable.
They are.
But that was not the cause of your error message.
He understood the message. ("Does this mean that the value returned is
the literal value? In this case 0.")
Left side was not a literal values.
What he did not understand was the
underlying situation. ("I would have assume a reference to the object
would have been returned and calling += would have unboxed the Integer
and aggregated the value.")
It still does not have anything to do with the fact that it was
an immutable object.
An expression on the left side of "=" does not work - immutable
or mutable.
Arne