IRIS Business Services Software Engineer Interview Questions and Answers

A Singleton Class is a class that can only have one instance and provides a global point of access to it.

• Singleton Class restricts the instantiation of a class to a single object.

• It is used when only one instance of a class is required throughout the system.

• It provides a global point of access to the instance.

• It is implemented by making the constructor private and providing a static method to access the instance.

• Exampl...read more

Static keyword in Java is used to create class-level variables and methods.

• Static variables are shared among all instances of a class

• Static methods can be called without creating an instance of the class

• Static blocks are used to initialize static variables

• Static import is used to import static members of a class

Singleton class ensures only one instance of a class is created and provides a global point of access to it.

• Create a private constructor to prevent direct instantiation of the class

• Create a private static instance of the class

• Create a public static method to get the instance of the class

• Ensure thread safety by using synchronized keyword or static initialization

• Example: Database connection manager

Hashmap is a data structure that stores key-value pairs and uses hashing to retrieve values quickly.

• Hashmap uses an array to store the key-value pairs

• The keys are hashed to generate an index in the array

• If two keys hash to the same index, a linked list is used to store the values

• Retrieving a value involves hashing the key to find the index and then traversing the linked list if necessary