How does Java Handle String Literals Setting to Null for Identical Values ?

Question

Suppose,
String s1="Java";
String s2="Java";
Now if i am not wrong only one value(bit pattern) "Java" exists in the heap and both s1 and s2 are pointing to it.
If i set s1 to null,
s1=null;
Won't s2 be affected (it is not getting affected actually..)
What could be the cause for this ?
Thanks in Advance.

Answer 1

amtidumpti wrote:
So is it something like ....
Variable         Memory Address   Value
s1                      0234234           "Java"
s2                      0234235           "Java"
is s1 is set to null :
Variable         Memory Address   Value
s1                      0234234           null
s2                      0234235           "Java"
No. In your model here, a variable's value is a String object. It's as if your entire house exists on my s1 paper, and an exact duplicate house with all the same contents exists on my s2 paper. In Java, no variable or expression ever holds an object. No value is ever an object.
It's more like this:
Variable         Memory Address         Value
s1                      0234234           11223344
s2                      0234235           11223344
is s1 is set to null :
Variable         Memory Address         Value
s1                      0234234           null
s2                      0234235           11223344and 11223344 is, roughly speaking, the "address" where the String object holding "Java" is stored.
And in both your model and mine, "Memory Address" is not the address that the variable holds. Rather, it is the address that corresponds to what we humans have named s1 and s2 for our convenience.
Edited by: jverd on Apr 10, 2009 11:43 AM