<code>initWithCapacity:</code> is declared in <code>NSMutableArray</code>, but I want to use it to initialize an <code>NSArray</code>. I there any solution?

Since <code>NSArray</code> objects are immutable (cannot change the objects they contain) there's no use in adjusting the capacity of <code>NSArray</code>s. The capacity is the number of objects an array can contain without reallocating memory. It is only used for optimization.