# Question Set 2 ## Java Programming * What is covariant? * Real life examples of features of OOPS. * What are wrapper classes? * Write a implementation for Predicate functional interface * Functional Interface implementation Dynamically with Lambda * Junit Test case for addition of two numbers * Difference between Java 7 and Java 8. * How to clone an object in Java? * Can a static inner class be present within a non-static class? * When do you get the ClassNotFound error in Java? * Does Java have pointers or references? * What is the difference between i++ and ++i in Java? * What is the Collections class and Arrays class in Java? * Maven exclusion and scope related questions * Reflection in Java. * What is an Enum in Java? * What is the Map collection in Java? * Difference between Enumerator and Iterator in Java * What is the difference between a static block and instance block in Java? * What is Generics in Java and how to implement mutable and immutable objects? ## Collections & Data Structures * Explain List, ArrayList and Set * Comparison of HashSet and HashMap in Java * What is the internal working of HashMap and HashSet in Java? * What is collision in HashMap/Hashtable in Java? * What is the use of Optional feature in Java 8? Can you provide an example? * What is the hierarchy of Collection and Exception classes in Java? ## Strings & Memory Management * String compare and string constant pool questions * How to check equality of two string literals * Why is String immutable if it can be assigned a new value? * How string variables are stored in memory? * What happens if a new variable is created with the same value? * How memory is allocated to String? ## Exception Handling * Explain ConcurrentModificationException * Revisit [checked and unchecked exceptions](https://tingreavinash.gitbook.io/the-tech-toolbox/question-answers/pages/fpxJZ09D2m7GmgtJcTXq#explain-checked-and-unchecked-exceptions.). * Exception hierarchy and why Throwable is used. * How to create custom exceptions. * Types of exception handling. * Checked vs unchecked exceptions. * Throw vs Throws vs Throwable. * Deciding between Checked or Unchecked exceptions for user defined exceptions ## Java 8 Features * Parallel Stream * Functional Interface * Difference between Stream API and Collections framework * Why static methods introduced in Interface from Java 8? * Can one functional interface extend another functional interface? * What is the difference between intermediate and terminal operation in stream API? * Map and filter * Functional Interface * Stream API * How to group elements in a stream using GroupBy? * How to sort elements in a stream using Sorted? * What are Terminal and Intermediary operations in the Stream API? ## Concurrency * What is future in Executor framework * Difference between submit and execute methods * How to use execute methods * Synchronization topic: serialized vs. synchronized and ways to achieve synchronization. * Threads: Thread limit, executor, etc. ## Design Patterns * Explain factory design pattern * What are design patterns * Explain design patterns used in your application with code ## SQL * SQL question to find the student with maximum cost ## Microservices * What is Microservice * Command used to access a container * Kubernetes commands * What is Kubernetes and its function * Producer, consumer, predicate, supplier * How to create and manage JMS. * What is Callable/Future and how to achieve async in Java? * What is ThreadPoolExecutor and how to manage threads using it? * How to get the result from an async operation? * How to handle exceptions from a Runnable? * What is ExecutorService and how does it differ from Error and Exception? * How to handle an OutOfMemoryError and what are the workarounds for it? ## Coding * Write code to get customer accounts by id * What is REST API * Conflicting questions about REST methods like POST for response data * Idempotent in REST API with example * Java Lambda expression - program to get employees from a List of List of employees whose age is less than 40 * Array Operations: Second max value from array * Design Patterns: Immutability, singleton ## JPA * What is JPA * What is Entity * What is Entity scan * ORM framework used * What is @Qualifier annotation * What is @Required annotation * How to use the remove in JPA cascading operations ## Git * Git merge conflict scenarios * Git commit scenarios ## JUnit & Testing * What is Mockito and why it is used * Explain Junit testing with example * What is Sonarqube ## Miscellaneous * What is Normalization in SQL (1NF, 2NF, BCNF, etc.)? * What is the difference between Pointers and References in C++? --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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