Use of alloc init instead of new

There are a bunch of reasons here: http://macresearch.org/difference-between-alloc-init-and-new

Some selected ones are:

• new doesn't support custom initializers (like initWithString)
• alloc-init is more explicit than new

General opinion seems to be that you should use whatever you're comfortable with.

Frequently, you are going to need to pass arguments to init and so you will be using a different method, such as [[SomeObject alloc] initWithString: @"Foo"]. If you're used to writing this, you get in the habit of doing it this way and so [[SomeObject alloc] init] may come more naturally that [SomeObject new].

Very old question, but I've written some example just for fun — maybe you'll find it useful ;)

#import "InitAllocNewTest.h"

@implementation InitAllocNewTest

+(id)alloc{
    NSLog(@"Allocating...");
    return [super alloc];
}

-(id)init{
    NSLog(@"Initializing...");
    return [super init];
}

@end

In main function both statements:

[[InitAllocNewTest alloc] init];

and

[InitAllocNewTest new];

result in the same output:

2013-03-06 16:45:44.125 XMLTest[18370:207] Allocating...
2013-03-06 16:45:44.128 XMLTest[18370:207] Initializing...

+new is equivalent to +alloc/-init in Apple's NSObject implementation. It is highly unlikely that this will ever change, but depending on your paranoia level, Apple's documentation for +new appears to allow for a change of implementation (and breaking the equivalency) in the future. For this reason, because "explicit is better than implicit" and for historical continuity, the Objective-C community generally avoids +new. You can, however, usually spot the recent Java comers to Objective-C by their dogged use of +new.