Java Interview Questions

• Basics
  • Why java and why not other languages ? Features of Java
  • How do you compile and Execute java
  • String Interview Questions
• OOP Concept
  • Why Classes and Objects
  • Why Encapsulation
  • Why Abstraction
  • Why Polymorphism
  • Why Inheritance
  • Association, Aggregation, Composition
  • https://www.heapwizard.com/oops-java-specific-questions/
• JVM
  • JVM, JRE and JDK
  • Compoenents of JVM
  • Architecture and how the code flow in JVM when you execute a java program
  • Class Loader and its role
• Garbage Collection
• Basics
  • static
  • final
  • Method Overloading and Method Overriding
  • Inner Class
  • Primitive and non primitive data type in jav
  • Access Modifers and NonAccess Modifiers
  • Enum
  • File, FileWriter , FileReader, BufferedWriter, BufferedReader  and PrintWriter 
  • InputStreamReader and OutputStreamWriter (For Image,Video and Audio Read and Write)
  • NIO
  • FileInputStream and FileOutputStream
  • Serialization and Deserialization
  • Serialization in java
  • Cloning in java
  • String and String pool in java
  • Instance initializer block
  • Autoboxing and Unboxing
  • vargs
  • Marker Interface
  • How to do you convert JSON to java object
• DataStructure
  • Complexity Of an Algorithm
  • Sorting Algorithm
  • Searching AlgorithmStack, Queue
• Collections Interview Questions
• Generics
  1. Why Generics in java? and What is Generic Class
  2. Generic Method
  3. Bounded Type Parameter
  4. Unbounded Wildcard
  5. Type Erasure
• Java 8
• Design Patterns
• Java Multithreading
• Java – Cryptography

• Other Java API
  • Lombok
  • JMH

Core Technical

• When to use what
  • When do you store data in database? when in source code and when in a properties file example of each
• Tell me about the project you have been working
  • how is it deployed on server
  • We server, Tomcat, JBOSS and IBM WAS
  • Difference between a Web Server and a App Server
  • How application server connect to Database server ? What JNDI ?
  • How do you store database
  • JAR, WAR and EAR in java
    • JAR Creation, Execution and Updation and JAR Manifest
  • How do you send files for communication between applications

Practical Question :

• Design a command prompt in Java
• Terms and Condition to be displayed
• How to do you write a text into a file
• A Registration form if given to you for development. DB Design and Validation Feel free to ask questions and add each and every validation possible
  • First Name and Last Name
  • Age
  • Address

Reference :

Java Interview Questions by baeldung

This article is part of a series:• Java Collections Interview Questions
• Java Type System Interview Questions (current article)• Java Concurrency Interview Questions (+ Answers)
• Java Class Structure and Initialization Interview Questions
• Java 8 Interview Questions(+ Answers)
• Memory Management in Java Interview Questions (+Answers)
• Java Generics Interview Questions (+Answers)
• Java Flow Control Interview Questions (+ Answers)
• Java Exceptions Interview Questions (+ Answers)
• Java Annotations Interview Questions (+ Answers)
• Top Spring Framework Interview Questions