Hyderabad Metro Rail Interview Questions and Answers

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

• Singleton pattern can be implemented by making the constructor private and providing a static method to access the instance.

• The pattern can be broken by using reflection to access the private constructor and create multiple instances.

• Another way to break the Singleton pattern is by using multiple class loaders in Java.

• Th...read more

HashMap internally uses an array of linked lists to store key-value pairs. To store duplicate keys, we can use a custom implementation of HashMap.

• HashMap internally uses an array of linked lists to handle collisions.

• To store duplicate keys, we can create a custom HashMap implementation that allows multiple values for the same key.

• One approach is to use a HashMap with values as lists, where each key can have multiple va

Use compensating transactions and distributed tracing for managing transaction and logging in case of service B failure.

• Implement compensating transactions to rollback changes made by service B in case of failure.

• Use distributed tracing to track the flow of requests and identify where the failure occurred.

• Implement retry mechanisms to handle transient failures in service B.

• Use circuit breakers to prevent cascading fail...read more