best coding practices

[ankur rathi]

which type of coding is efficient or best practice :

class Other {
MyClass ob ;
void m() {
ob = new MyClass();
}

class Other {
void m() {
MyClass ob = new MyClass();
}

Note : we are not using reference of MyClass outside of this method .

thanks a lot .

[Tony Morris]

The latter. Encapsulation is of utmost importance.
Do not expose the reference to a greater scope than it needs to be.

[Vicken Karaoghlanian]

In your first example, 'MyClass' object will be eligible for GC iff:
1) You explicitly set its reference to null.
2) Class 'Other' is EGC

However in the second example the object will be eligible for GC as soon as m() method exits.

From Memory-Usage point of view, i'll go with the second code sample.

[ankur rathi]

Vivek ,
In first case also , object will be eligible for GC as soon as the method will get complete .
[ February 07, 2005: Message edited by: rathi ji ]

[Vicken Karaoghlanian]

Originally posted by rathi ji:
Vivek ,
In second case also , object will be eligible for GC as soon as the method will get complete .

Yes that is true, but the real question is how soon the object will be EGC. Get it?

It is really frustrating how people misspell my name , it is not Vicky, Vivek, Velder, or any other awkward combination. It is simply pronounced V-I-C-K-E-N, think of it as a combination of Vicky and Ken (just drop the y). Thank you for your time and happy ranching.

My apologies rathi if i sounded harsh, nothing personal is intended.
[ February 05, 2005: Message edited by: Vicken Karaoghlanian ]

[ankur rathi]

Yes that is true, but the real question is how soon the object will be EGC. Get it?

Not vicken ... please help .

thanks .

[Srinivas Velamuri]

Please refer to the following link, which explains the differences between instance variables and local variables:
web page

[Mike Gershman]

In first case also, object will be eligible for GC as soon as the method will get complete.

I don't think so.

In the first case, the myClass object will last at least as long as the Other object. In the second case, the myClass object will be eligible for collection as soon as method m() returns and the stack frame holding ob is discarded.

[Jeroen Wenting]

Mike is right. Instance members can't get GC'd until either the instance they belong to gets GC'd or they are explicitly set to null.

[ankur rathi]

It means , we can use that reference outside that method code as well .

Please comment .

thanks .

[Jeroen Wenting]

yes, instance variables are available to any method in the class as well as by any other class which has access to members with the relevant access privileges for that instance variable.

Automatic variables are available only to the method in which they were created (or in very specific cases to instances of inner classes defined and created within that same method).

[Mike Gershman]

Automatic variables
That's not a Java term. Are you thinking FORTRAN 90 or PL/I or ???