Core Java Interview Questions

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 Core Java Interview Preparation 


Welcome Friends to the Bright Tech Bits, in this post I am trying to cover the most asked interview questions for Java, Spring Boot, and Microservices. These questions are helpful for freshers as well as experienced ones.


  • What is Method Hiding - static method overriding  in subclass 
  • String constant pool
  • List the different collections you are aware of.
  • What is fail-safe and fail fast iterators
  • Questions on Hashmap internal working 
  • Difference between comparable and comparator interface.
  • Difference between Array and ArrayList 
  • Difference between HashMap and ConcurrentHashMap
  • What is serialization and externalization, use of transient keyword
  • Checked/Unchecked Exceptions
  • How to create our own custom checked execption
  • What is need of serialization.
  • What is diff between wait and notify method in multithreading.
  • Design Patterns - Creational , structural, Behavioral 
  • Singletone Design pattern implementations 
  • How to break singleton design pattern


    • Below are the questions for the Java 8 version as it was major changes in this version and a lot of new concepts were introduced.
    • Lambda expression
    • Functional Interfaces, implicit functional interfaces 
    • Can a functional interface extend/inherit another interface?
    • What are static methods in Interfaces?
    • Default methods 
    • Method References and Its Types 
    • Stream API - Examples on Filtering and Sorting
    • Optional Class and Its Uses 



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