Principal Global Services Trainee Interview Questions and Answers

Abstraction is the process of hiding complex implementation details and exposing only the necessary information.

• Abstraction is achieved through the use of abstract classes and interfaces.

• It helps in reducing complexity and making code more maintainable.

• Abstraction allows for better separation of concerns and promotes modularity.

• Examples of abstraction include the use of APIs and libraries.

• Abstraction is a key concept i

Creating threads involves dividing a program into smaller tasks that can run concurrently. Filters are used to process data.

• Threads allow for parallel processing and can improve performance.

• Filters are used to manipulate data by applying a set of rules or conditions.

• Examples of filters include sorting, searching, and transforming data.

• Filters can be applied to threads to process data in parallel.

An application container is a lightweight, standalone executable package that contains everything needed to run an application.

• Application containers provide a way to package and deploy applications in a consistent and reproducible way.

• They isolate the application from the underlying system, making it portable across different environments.

• Examples of container technologies include Docker, Kubernetes, and OpenShift.

Bean not found exception occurs when a requested bean is not present in the container.

• Occurs during runtime when a bean is not defined in the application context

• Can be caused by typos in bean names or incorrect configuration

• Can be resolved by defining the missing bean or correcting the configuration

Serialization is the process of converting an object into a format that can be stored or transmitted.

• Serialization is used to transfer data over a network or to store it in a file.

• It involves converting an object into a stream of bytes or characters.

• The serialized data can then be deserialized back into an object.

• Serialization is commonly used in programming languages like Java and C#.

• Examples of serialization formats ...read more

RDBMS is a relational database management system while NoSQL is a non-relational database management system.

• RDBMS stores data in tables with predefined schema while NoSQL stores data in documents, key-value pairs, or graphs.

• RDBMS supports ACID transactions while NoSQL sacrifices ACID for scalability and flexibility.

• RDBMS is best suited for structured data while NoSQL is best suited for unstructured or semi-structured d...read more

Runtime polymorphism is the ability of an object to take on many forms.

• It allows a subclass to provide its own implementation of a method that is already provided by its parent class.

• It is achieved through method overriding.

• Example: Animal class has a method called 'makeSound'. Dog and Cat classes extend Animal and override the 'makeSound' method to bark and meow respectively.

Controller is a basic Spring MVC controller while RestController is used to create RESTful web services.

• Controller is used for traditional web applications while RestController is used for RESTful web services.

• RestController returns data in JSON or XML format while Controller returns data in HTML format.

• RestController is annotated with @RestController while Controller is annotated with @Controller.

• RestController is a s...read more

Stream API is a Java API that allows processing of collections of objects in a functional way.

• Stream API provides a set of functional interfaces to perform operations on collections.

• It supports parallel processing of collections.

• It can be used to filter, map, reduce, and sort collections.

• Example: List numbers = Arrays.asList(1, 2, 3, 4, 5); numbers.stream().filter(n -> n % 2 == 0).forEach(System.out::println);

• Example: ...read more

An interface is a blueprint for a class while a functional interface is an interface with only one abstract method.

• An interface can have multiple abstract methods while a functional interface has only one.

• Functional interfaces can be used with lambda expressions and method references.

• Examples of functional interfaces include Runnable, Comparator, and Callable.

• Interfaces can have default and static methods while functio...read more