Optum Global Solutions Software Engineer Interview Questions and Answers

Joins are SQL operations that combine records from two or more tables based on related columns.

• INNER JOIN: Returns records with matching values in both tables. Example: SELECT * FROM A INNER JOIN B ON A.id = B.id;

• LEFT JOIN: Returns all records from the left table and matched records from the right table. Example: SELECT * FROM A LEFT JOIN B ON A.id = B.id;

• RIGHT JOIN: Returns all records from the right table and ma...read more

Implementing a linked list involves defining nodes, linking them, and providing methods for insertion, deletion, and traversal.

• Define a Node class with data and a pointer to the next node.

• Create a LinkedList class to manage the head node and operations.

• Implement methods for insertion (at head, tail, or specific position).

• Implement methods for deletion (by value or position).

• Provide traversal methods to display the...read more

An IoC container manages object creation and dependencies, promoting loose coupling and easier testing in software applications.

• IoC containers handle the instantiation and lifecycle of objects, reducing manual dependency management.

• They support Dependency Injection (DI), allowing dependencies to be provided externally rather than hard-coded.

• Examples include Spring Framework (Java), .NET Core's built-in IoC contain...read more

Java 8 introduced significant features like lambdas, streams, and the new Date-Time API, enhancing productivity and code readability.

• Lambda Expressions: Enable functional programming by allowing you to pass behavior as a parameter. Example: (x, y) -> x + y.

• Streams API: Facilitates processing sequences of elements (collections) in a functional style. Example: list.stream().filter(x -> x > 10).

• Default Metho...read more

Use bubble sort algorithm to rearrange the array in decreasing order.

• Iterate through the array and compare adjacent elements, swapping them if they are in the wrong order.

• Repeat this process until the array is sorted in decreasing order.

• Example: ['apple', 'banana', 'cherry'] -> ['cherry', 'banana', 'apple']

Sort a linked list

• Use a sorting algorithm like merge sort or quick sort

• Traverse the linked list and rearrange the nodes accordingly

• Ensure to update the head of the linked list after sorting

To restrict a class from being inherited, mark it as final.

• Use the final keyword before the class declaration.

• Final classes cannot be subclassed.

• Any attempt to subclass a final class will result in a compile-time error.