Go Language Interview Questions and Answers

1. What is Go language and what are its key features?

Ans: Go is an open-source programming language developed by Google. Its key features include simplicity, concurrency support, garbage collection, and fast compilation.

2. What is a Goroutine in Go?

Ans: Goroutine is a lightweight thread of execution in Go. It enables concurrent programming and allows multiple functions to run concurrently.

3. How do you handle errors in Go?

Ans: In Go, error handling is explicit. You can use the 'error' type to represent errors, and functions can return errors to indicate failure. Error checking is typically done using the 'if err != nil' pattern.

4. Explain the difference between defer, panic, and recover in Go.

Ans: Defer is used to schedule a function call to be executed after the surrounding function returns. Panic is used to cause a runtime error and stop the normal execution of a function. Recover is used to catch and handle a panic, allowing the program to continue executing.

5. What is the purpose of the init function in Go?

Ans: The init function is a special function in Go that is automatically called before the main function. It is typically used for package initialization tasks.

6. How do you handle concurrent programming in Go?

Ans: Go provides Goroutines and channels for concurrent programming. Goroutines are lightweight threads, and channels are used for communication and synchronization between Goroutines.

7. Explain the difference between slices and arrays in Go.

Ans: Arrays have a fixed size defined at compile time, while slices are dynamically sized and can be resized. Slices are more commonly used in Go.

8. How do you handle JSON in Go?

Ans: Go provides the encoding/json package, which allows you to encode Go data structures into JSON and decode JSON into Go data structures.

9. What is the purpose of the blank identifier in Go?

Ans: The blank identifier, represented by an underscore (_), is used to ignore a value or a package during compilation or assignment when you don't need it.

10. Explain how to handle file operations in Go.

Ans: Go provides the os and ioutil packages for file operations. You can open, read, write, and manipulate files using these packages.

11. What is the purpose of the sync package in Go?

Ans: The sync package provides synchronization primitives like Mutex, WaitGroup, and Cond, which are useful for managing shared resources and coordinating Goroutines.

12. How do you handle concurrent access to shared data in Go?

Ans: Go provides synchronization primitives like Mutex and RWMutex to protect shared data from concurrent access. Proper locking mechanisms must be used to ensure data integrity.

13. What is the difference between defer and finally in other programming languages?

Ans: Unlike other programming languages, Go does not have a finally keyword. However, defer statements in Go can be used to achieve similar functionality by scheduling code to run after a function returns.

14. How do you handle command-line arguments in Go?

Ans: Command-line arguments can be accessed using the os.Args variable. It provides a slice of strings where the first element is the program name.

15. How do you write unit tests in Go?

Ans: Go has a built-in testing package called "testing" that provides functions for writing unit tests. Test functions should be named with the "Test" prefix and accept a pointer to the testing.T type as an argument.

16. Explain the concept of interfaces in Go.

Ans: Interfaces in Go are a collection of method signatures. They define behavior that a type must implement. Any type that satisfies the interface implicitly implements the methods defined by the interface.

17. What is the purpose of the context package in Go?

Ans: The context package in Go is used for managing and propagating cancellation signals, deadlines, and request-scoped values across Goroutines.

18. How do you handle errors in Goroutines in Go?

Ans: In Go, it's recommended to use the "error return" pattern to propagate errors from Goroutines. Errors can be collected and processed at the caller's level.

19. Explain the concept of pointers in Go.

Ans: Pointers in Go allow you to directly manipulate memory addresses. They are useful when you want to modify a variable's value directly or when passing large data structures efficiently.

20. How do you work with database/sql package in Go?

Ans: Go's database/sql package provides a uniform interface for working with SQL databases. It supports various database drivers and provides functions for executing queries, transactions, and managing connections.

21. What is the purpose of the defer statement in Go?

Ans: The defer statement in Go is used to schedule a function call to be executed after the surrounding function returns. It is often used for resource cleanup and ensuring certain operations are always performed.

22. How do you handle concurrent access to maps in Go?

Ans: Concurrent access to maps in Go can lead to race conditions. To safely access maps from multiple Goroutines, you can use synchronization primitives like the sync.Mutex or sync.RWMutex.

23. What are channels in Go, and how are they used?

Ans: Channels in Go provide a way for Goroutines to communicate and synchronize with each other. They are used to send and receive values between Goroutines, ensuring safe and synchronized communication.

24. What is the difference between the "make" and "new" functions in Go?

Ans: The "make" function is used to create slices, maps, and channels in Go, while the "new" function is used to allocate memory for a value and return a pointer to it.

25. How does garbage collection work in Go?

Ans: Go uses a concurrent garbage collector that runs concurrently with the program's execution. It automatically detects and reclaims memory that is no longer in use, reducing the burden on developers for manual memory management.