Can we do nil or NULL in dealloc method and releasing that variable?

Question

- (void)dealloc 
{
    [refreshProgressInd release];
    [DetailsObject release];
      List=nil;
    [List release];
    [mapView release];
     addAnnotation=nil;
    [addAnnotation release];
    [reverseGeocoder release];
    [super dealloc];
}

Answer 1

Don't set a variable to nil before releasing it, otherwise the release message gets discarded when it should have been sent to an object.

[someObject release];
someObject = nil;

Keep in mind that dealloc is the last thing to be invoked before your object is actually deallocated, so setting variables to nil is often unnecessary.