Unisys Interview Questions and Answers

Semaphore and mutex are synchronization mechanisms used in multi-threaded environments.

• Semaphore allows multiple threads to access a shared resource simultaneously, while mutex allows only one thread at a time.

• Semaphore is used to control access to a pool of resources, while mutex is used to protect a single resource.

• Semaphore uses a counter to keep track of the number of available resources, while mutex uses a lo...read more

Find the repeating number in an array.

• Iterate through the array and store each element in a hash table or set.

• If an element is already present in the hash table, it is a repeating number.

• Alternatively, sort the array and check for adjacent elements with the same value.

• Time complexity: O(n) or O(nlogn) depending on the approach used.

Paging and segmentation are memory management techniques used by operating systems.

• Paging divides memory into fixed-size pages and stores data in these pages.

• Segmentation divides memory into logical segments and stores data in these segments.

• Paging is simpler and more efficient, but can lead to external fragmentation.

• Segmentation is more flexible, but can lead to internal fragmentation.

• Both techniques are used to ...read more

Stack is LIFO and Queue is FIFO data structure. Stack is like a stack of plates and Queue is like a queue of people.

• Stack is Last In First Out (LIFO) and Queue is First In First Out (FIFO)

• Stack is like a stack of plates where the last plate added is the first one to be removed

• Queue is like a queue of people where the first person to enter is the first one to leave

• Stack is used in undo-redo functionality in text ed...read more

Oops concepts in Java refer to Object-Oriented Programming principles like Inheritance, Encapsulation, Polymorphism, and Abstraction.

• Inheritance: Allows a class to inherit properties and behavior from another class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Polymorphism: Ability of a method to do different things based on the object it is acting upon.

• Abstraction: Hiding th...read more

Designing microservices involves breaking down a monolithic application into smaller, independent services.

• Identify the boundaries of each microservice based on business capabilities

• Decide on communication protocols between microservices (REST, messaging, etc.)

• Implement fault tolerance and scalability measures for each microservice

• Use containerization (Docker) and orchestration tools (Kubernetes) for deployment

• Mon...read more