Comprehensive Java Concepts and Key Features Explained
1. What is Java and Explain Features of Java?
2. Why is Java a Platform Independent Language?
3. What is Byte Code and the Importance of Byte Code?
4. What is the Difference Between Byte Code and Machine Code?
5. What is the Difference Between Platform Independency and Cross Platform?
6. What is OOP and Explain in Depth?
7. What are the Pillars of OOP?
8. What is the Difference Between Semi Object Oriented and Pure Object Oriented?
9. What is JDK, JRE, and JVM?
10. What is the Difference Between JDK, JRE, and JVM?
11. What is JVM and Explain its Architecture?
12. What is an Array and How Many Ways to Declare an Array in Java?
13. What is the Difference Between C Array and Java Array?
14. What is a Jagged Array in Java?
15. What is an Anonymous Array in Java?
16. What is a Class and Why Use It?
17. How Can We Reuse a Class More Than One Time?
18. What is Encapsulation and Explain Encapsulation with a Real-Time Scenario?
19. What is the Difference Between Instance Variable, Static Variable, and Local Variable?
20. What is the Static Keyword and Explain Static Variable, Static Method?
DAY 2
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Q1. Explain Any 4 Important Points Related to Static and Instance Variables?
Q2. What are Method Variable Arguments?
Q3. What is an Array of Objects and How to Create an Array of Objects in Java?
Q4. What is the Meta Section and Why Use It?
Q5. Is it True Static Variable is Not Stored in an Object?
Q6. Is it True Static Variable is Stored in the Meta Section?
Q7. Is it True Instance Variable Allocates Memory After an Object?
Q8. Is it True We Cannot Declare a Class as Private, Static, and Protected?
Q9. What is a Nested Class?
Q10. What is a Constructor and Why Use a Constructor?
Q11. Explain Types of Constructors?
Q12. What is Constructor Overloading Explained with an Example?
Q13. What is Constructor Chaining and Explain this() Constructor?
Q14. What is a Singleton Class and How to Create It?
Q15. What is a Utility Class in Java and How to Create It?
Q16. What is Inheritance and Why Use It?
Q17. Explain Types of Inheritance in Java?
Q18. Can We Create a Java Program Without Inheritance?
Q19. Why is the Object Class the Parent of Every Class in Java?
Q20. Is it True if Parent Contains Default Constructor, Then it is Executed Before Child?
Q21. Is it True if Parent Contains Parameterized Constructor, Then Programmer Must Pass Parameter from a Child?
Q22. What is super() Constructor and Why Use It?
Q23. Is it Possible to Write a super() Constructor on the Second Line of Code?
Q24. Is it Possible to Use super() and this() at the Same Time?
Q25. Is it True that super() Passes Parameters to the Immediate Parent Class?
DAY 3
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Q1. What is the Final Keyword and Explain in Depth?
Q2. How Can We Avoid Method Overriding in Java?
Q3. Why Use Method Overriding and Explain its Benefit?
Q4. Is Method Overriding Beneficial Every Time?
Q5. What is the Difference Between Static and Final Variables?
Q6. Can We Use Static and Final at the Same Time?
Q7. Can We Override the Final Method in Java?
Q8. What is an Abstract Class and Abstract Method?
Q9. What is Abstraction in Java and How Can We Achieve It?
Q10. What is the Difference Between Abstraction and Encapsulation?
Q11. What is the Difference Between Final and Abstract Methods?
Q12. Is it True that Abstract Methods Must be Overridden in Child Class?
Q13. Can We Override the Constructor?
Q14. Can We Declare a Constructor as Abstract?
Q15. Can We Declare the Constructor as Final?
Q16. Can We Declare Abstract Methods as Static?
Q17. Can We Declare an Abstract Method as Final?
Q18. Can We Declare Abstract Methods as Private?
Q19. Can We Declare Abstract Methods as Protected?
Q20. Can We Declare Methods as Protected in Parent and Override as Public?
Q21. Can We Declare a Method as Protected in Parent and Override as Default?
Q22. Can We Declare a Method as Public in Parent and Override as Default or Protected?
Q23. What is the Difference Between Overloading and Overriding?
Q24. What is the Difference Between Static and Final?
Q25. What is the Difference Between Static and Abstract?
DAY 4
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Q26. What is a Concrete Class in Java?
Q27. What is an Adapter Class and Why Use It and How to Create It?
Q28. What is an Interface in Java?
Q29. Is it True Interface Variable is by Default Public Static Final?
Q30. Can I Define a Method Within the Interface?
Q31. Is it True Interface is Used to Achieve 100% Abstraction?
Q32. Can We Declare Interface Methods as Protected?
Q33. Can We Declare Interface Methods as Static with Reason?
Q34. Can We Declare Interface Methods as Public?
Q35. Can We Inherit One Interface to Another Interface Using Extends Keyword?
Q36. Can We Implement Interfaces in Class?
Q37. How to Solve Diamond Problems Using an Interface?
Q38. How to Achieve Multiple Inheritance Using Interface?
Q39. What is the Difference Between Interface and Abstract Class?
Q40. Can We Override the Static Method?
Q41. What is Method Hiding in Java and Explain in Detail?
Q42. What is the Difference Between Hiding and Overriding?
Q43. What is Dynamic Polymorphism and How Can We Achieve It in Java with Code?
Q44. What is Coupling in Java and Explain in Detail?
Q45. What is IS-A Relationship and What is HAS-A Relationship in Java?
DAY 5
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Q1. What is an Exception and Why Use It?
Q2. Explain Exception Handling Hierarchy?
Q3. Explain Benefits of Exception Handling?
Q4. Explain Types of Exception in Java?
Q5. What is the Difference Between Exception and Error?
Q6. Explain Keywords for Exception Handling with Examples?
Q7. What is the Difference Between Catch and Finally Block?
Q8. What is the Throws Keyword in Exception Handling and Why Use It?
Q9. What is the Throw Keyword in Exception Handling and Why Use It?
Q10. What is the Difference Between Throws and Throw Keyword?
Q11. Explain Any 10 Exceptions with Example?
Q12. Can We Write Try Without Catch Block?
Q12. What is Try with Resource Bundle?
Q13. Can We Write More Than One Exception in Catch Block Using Pipe Operator?
Q14. Can We Write Try Within Try Block?
Q15. Can We Write Multiple Catch for Single Try?
Q16. Is it True Throw and Throws Throw Exception Object at Function Calling Point?
Q17. Is it True Throws is Designed to Handle Checked Exception?
DAY 6
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Q1. What are Wrapper Classes in Java and Why Use It?
Q2. Explain Type Casting and Its Type?
Q3. What is Implicit Type Casting and Explicit Type Casting?
Q4. Explain Hierarchy of Wrapper Classes in Java?
Q5. Explain Number Class and Its Child Classes with Its Method?
Q6. What is Autoboxing and Auto Unboxing in Wrapper Classes?
Q7. Explain Use of xxxValue() Method of Number Class with Example?
Q8. Explain valueOf() Method of Wrapper Classes?
Q9. What is the parseXXX() Method of Wrapper Classes?
Q10. What Does String in Java Explain in Depth?
Q11. What is the Meaning of Immutable in Java?
Q12. How Many Ways to Create Strings in Java?
Q13. What is the Difference Between String Creation Using ” ” and Using a New Keyword?
Q14. What is a String Constant Pool?
Q15. Explain Any 4 Constructors of String Class Constructor?
Q16. Explain charAt(), length(), indexOf(), substring(), split(), trim(), concat(), toUpperCase(), toLowerCase() Methods with Its Syntax and Code Examples?
Q17. State the Difference Between String in C and String in Java?
Q18. Can We Use String in the Switch Case as a Choice?
Q19. Is String Thread Safe in Java?
Q20. What is StringBuffer and StringBuilder in Java?
Q21. Can We Use StringBuffer and StringBuilder Using Initialization Technique?
Q22. What is the Difference Between String, StringBuffer, and StringBuilder in Java?
Q23. Explain append(), delete(), and insert() Method of String in Java?
Q24. What Does the String intern() Method Do?
DAY 7
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Q1. What is a Thread in Java?
Q2. What is Multithreading in Java?
Q3. What is the Benefit of Multi-Threading?
Q4. What is the Process?
Q5. What is the Difference Between Process and Thread?
Q6. How Many Ways to Create Threads in Java Explain with Examples?
Q7. How to Create a Thread in Java Using Thread Class?
Q8. Explain Thread Class All Methods?
Q9. Is it True that Runnable Contains the run() Method?
Q10. Is it True that the Runnable Interface is Implemented by the Thread Class?
Q11. Is it True that Runnable is a Marker Interface?
Q12. Explain the Life Cycle of Thread?
Q13. Explain isAlive(), join(), start(), run(), sleep(), stop(), yield(), setPriority(), getPriority(), wait(), notify(), and notifyAll() Methods?
Q14. What is the Difference Between wait() and sleep() Method?
Q15. What is Synchronization and Asynchronization in Java?
Q16. What is Thread Priority in Java and Explain All Types of Thread Priority?
Q17. What is a Daemon Thread in Java?
Q18. Can We Create a User Thread as a Daemon Thread?
Q19. Why Do We Need to Implement Thread Using a Runnable Interface?
Q20. Write Code for Creating Thread Using Runnable Interface?
DAY 8
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Q1. What are Streams in Java and Why Use It?
Q2. How Many Ways to Work with File in Java?
Q3. Explain File Class from java.io Package?
Q4. Explain How to Get All Drive Names, Total Space of Drive, Free Space of Drive, etc.?
Q5. Explain Hierarchy of OutputStream Class?
Q6. Explain Hierarchy of Writer Class?
Q7. Explain Methods of Writer Class?
Q8. Explain Methods of OutputStream Class?
Q9. Explain FileWriter Class with Its Constructor and Write Code for Storing Data in .txt File?
Q10. Explain BufferedWriter Class with Example?
Q11. What is the Difference Between FileWriter and BufferedWriter Class?
Q12. Explain FileReader and BufferedReader with Example?
Q13. Explain ObjectOutputStream Class?
Q14. Explain ObjectInputStream Class?
Q15. What is Serialization and Deserialization in Java?
Q16. Write Code for Serialization and Deserialization in Java?
Q17. Write Code for Reading .csv Files in Java?
DAY 9
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Q1. What is Collection and Why Use Collection Framework? Explain with 5 Reasons?
Q2. What are the Benefits of Collection Over Array?
Q3. Explain Collection Hierarchy?
Q4. Explain Iterable Interface in Java with Its Method?
Q5. What is Collection Interface and Explain All Methods of Collection Interface?
Q6. Explain add() Method, Boolean contains() Method, indexOf() Method, size(), Boolean isEmpty(), remove(), iterator() Method, etc.
Q7. Explain Types of Collection Like List, Set, and Queue Interface?
Q8. What is the Difference Between List and Set Interface?
Q9. What is the Difference Between List and Queue Interface?
Q10. Explain All Implementer Classes of Collection Framework?
Q11. Explain Vector Class with Its Constructor?
Q12. Explain Any 5 Important Points of Vector Class?
Q12. Is it True Vector is Synchronized Collection and Explain Its Reason?
Q13. Is it True Vector is Legacy Collection?
Q14. What is Legacy Collection in Java?
Q15. What is Default Capacity of Vector?
Q16. Is it True Vector Occupies Double Memory Than Its Current Capacity?
Q17. Explain Logic of Vector Double Capacity Increment?
Q18. What is the Difference Between Vector and ArrayList?
Q19. What is Default Capacity of Vector and ArrayList Collection?
Q20. How ArrayList Increases Its Capacity When Capacity Crosses?
Q21. What is the Difference Between LinkedList and ArrayList?
Q22. What is Time Complexity of LinkedList?
Q23. What is Time Complexity of ArrayList?
Q24. Who is Better for Element Deletion or Updation Between LinkedList and ArrayList?
Q25. Who is Better for Data Fetching or Data Retrieval Between LinkedList and ArrayList?