Bounteous x Accolite Java Developer Interview Questions and Answers

Find the length of the longest subsequence of contiguous integers in an array.

• Sort the array

• Iterate through the array and check for consecutive integers

• Keep track of the longest subsequence found

Use flatMap and map to extract list of pincodes from Employee objects

• Use flatMap to flatten the list of Addresses in each Employee object

• Use map to iterate over the flattened list and extract the pincodes

• Example: employeeList.stream().flatMap(emp -> emp.getAddresses().stream()).map(address -> address.getPincode()).collect(Collectors.toList())

Database pooling is a technique used to manage a pool of database connections for efficient resource utilization. HikariCP is a popular database connection pooling library in Java.

• HikariCP is a high-performance database connection pooling library for Java applications.

• It is known for its low latency and high throughput.

• Configurations for HikariCP include settings such as maximum pool size, connection timeout, and idle timeout.

• Example: HikariConfig config = new HikariConfig();...read more

Singleton is a creational design pattern that ensures a class has only one instance and provides a global point of access to it.

• To create a Singleton, make the constructor private to prevent direct instantiation

• Create a static method that returns the instance of the class

• Use lazy initialization to create the instance only when it's needed

• Ensure thread safety by using synchronized keyword or double-checked locking

• Examples: java.lang.Runtime, java.awt.Desktop, java.util.Calenda...read more

Method overriding in Java with code example

• Output will be 'Child class method' as the method in Child class overrides the method in Parent class

• Method overriding is a feature that allows a subclass to provide a specific implementation of a method that is already provided by its superclass

• The method in the subclass should have the same name, return type, and parameters as the method in the superclass

To fetch all duplicate values from an array of strings

• Iterate through the array and store each element in a HashSet

• If an element is already in the HashSet, it is a duplicate value

• Add the duplicate values to a separate list and return it

Use a nested loop to iterate through the array and check for the sum of squares of two elements equal to the square of a third element.

• Iterate through the array using a nested loop to compare all possible combinations of elements.

• Calculate the sum of squares of two elements and check if it equals the square of a third element.

• Return the elements if a match is found, otherwise continue iterating.

API to save data in Java

• Use HTTP POST method to send data to the server

• Create a RESTful endpoint to handle the data saving

• Validate the input data before saving it to the database