Demonstrates problem with static methods

gistfile1.m

@interface Foo : NSObject

+ (void)bar;

@end

@implementation Foo

+ (void)bar {
    
}

@end

@interface Baz : NSObject

@end

@implementation Baz

+ (void)initialize {
    if (self == [Baz class]) {
        [self bar]; // No known class method for selector 'bar'. Yay!
    }
}

- (id)init {
    self = [super init];
    if (self) {
        [[self class] bar]; // No errors. Boo!
    }
    return self;
}

@end

There are at least two code smells here:

• Sending messages to self in -init and +initialize is fragile due to the potential for side effects on an object that's not fully initialized.
• If Baz was subclassed, +bar may not be what you want anymore. The call at :30 should explicitly refer to Baz instead of [self class].