Updated September 1, 2026
Objective-C is a programming language that was developed in 1980. It can be said to be a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to C programming. This is mainly famous because it was the primary language Apple used to build the macOS and iOS operating systems. Later, it was also selected as the main language that was to be used by NeXT. Below are a few questions that can be asked in an Objective-C interview.
If you are looking for a job related to Objective-C, you need to prepare for the 2026 Objective-C Interview Questions. Every interview is indeed different depending on the job profile. Here, we have prepared important Objective-C Interview Questions and Answers to help you succeed in your interview.
Objective-C Interview Questions and Answers for Freshers
In this article, we shall present the 10 most important and frequently asked Objective-C interview questions. These questions are divided into two parts, as follows:
Part 1 – Objective-C Interview Questions (Basic)
This first part covers basic Objective-C interview questions and Answers.
Q1. How do you manage Objective-C?
Answer:
Memory in Objective-C is done dynamically. This means memory is allocated during the runtime of any program. It is being utilized, and later it is freed when it is no longer required. This helps in using as little memory as possible. In this entire lifecycle of memory, the objects take up as much memory as they need and then free them when it is not required. For allocating memory in Objective-C, there are two ways:
- Manual Retain Release (MRR): In this type of memory management, memory is explicitly managed, and all objects are tracked. It uses the reference-counting model to keep track of this.
- Automatic Reference Counting (ARC): Here, the system can insert appropriate memory management method calls, which are called the runtime.
The two main drawbacks of memory management are that freeing memory too aggressively can cause multiple system crashes, and failing to free it can lead to memory leaks, which increase the application’s in-memory footprint.
Q2. What are declared properties in Objective-C?
Answer:
In Objective-C, any property that is to be used can be defined by declaring different instance variables by implementing getter and setter methods that help enforce encapsulation. There are three aspects to properties. These include the declaration, implementation, and access. The properties can be declared in any class, category, or protocol in the declarative section. The syntax for this is as follows:
@property(attributes…)type propertyName
It also has optional attributes. Attributes can be as follows:
- Readonly: This property can only be read and not written to. This compiler does not have a setter accessor.
- Read-write: This property enables both reading and writing. The default mode is read-only.
- Assign: This is a simple assignment that can be used in the implementation of any setter.
- Retain: Retain is sent to the property once it is assigned.
- Copy: Like retain, this operation is also performed once the property is assigned.
Let us move to the next Objective-C Interview Questions.
Q3. What are the characteristics of a category?
Answer:
A category has the following characteristics: A category should be declared for any class even though there is no original source code available for implementation. The methods that are defined in a particular category are available for all instances to the class where it actually belongs. It can also be used in the subclasses of the original class, such as in inheritance. There should not be any variation in a method that is appended by any category. Once the original class implements it, it can be used at runtime.
Q4. What is Retain count?
Answer:
This is a basic Objective-C interview question. The ownership policy is implemented via reference counting. This retain count is taken after the retain method. Each object has a retain count, and when an object is created, its default retain count is 1. When this newly created object is sent as a retain message, the count increases by 1. This count is decreased by 1 when an object is sent as the release message. It also decreases when an object is sent an autorelease message at the end of the current autorelease pool. The object is released and deallocated when its retain count is decreased to 0.
Q5. When do we use NSArray and NSMutableArray?
Answer:
NSArray is recommended when the array’s contents will not change. An example of this is a company name that changes seldom; hence, an NS Array can be used so that no one can manipulate it.
NSMutable Array: Unlike NS Array, this array is used when the array’s contents tend to change. Here, an example can be considered a function that takes the array as an argument, and this function will append some elements to that array. At this time, an NSMutable array can be used.
Part 2 – Objective-C Interview Questions (Advanced)
Let us now have a look at the advanced Interview Questions.
Q6. Is it possible to use ARC and Non-ARC code together in a project?
Answer:
Yes, a project can use both ARC and Non-ARC codes. When a project chooses Non-ARC codes, then –fobj-arc compiler flag is set. This ARC can be disabled for specific classes by using –fno-objc-arc.
This entire process can be done by Xcode → Project→ Build Phase→ Compile Sources→ Double Click on the class and set the–fno–objc–arc.
Q7. What are the methods of using the NSURL connection?
Answer:
The methods that can be used in an NSURL connection are the following:
- A connection that received the response
- A connection that receives data
- A connection that fails with an error
- A Connection that did finish loading
Let us move to the next Objective-C Interview Questions.
Q8. What is the protocol in Objective-C?
Answer:
A protocol is a language feature that provides multiple inheritance in a language with single inheritance. Objective-C mainly supports two protocols:
Formal protocols are also known as compiler protocols, and informal protocols as ad hoc protocols.
Q9. How does the message work in Objective-C?
Answer:
These are the most frequently asked Objective-C interview questions. Messaging is not bound to happen until a method is implemented in Objective-C. A call messaging function objc_msgSend() is called when the compiler transforms a message expression. This function connects to the receiver, and the name of the method is mentioned in the message.
Q10. What is atomic and non-atomic in Objective-C, and which one is considered to be the default?
Answer:
This method is used to specify the accessor methods that are not atomic. This ensures that the CPU completes the process that is currently being run before any other process accesses the variable. Non-atomic is for the non-atomic variables. These are faster but not thread-safe.
Recommended Articles
This has been a guide to Objective-C Interview Questions and Answers. Here we have listed the 10 most useful sets of interview questions to help the job seeker crack the interview with ease. You may also look at the following articles to learn more –
