Advanced Java Interview Questions and Answers for Coding Interview

Java is an Object-Oriented programming language used by the vast majority of programmers worldwide. Around 3,77,483 companies use Java. Technical interviews at top companies frequently include advanced Java interview questions based on coding and programming theory.

If you are preparing for a Java developer or software engineering interview, these advanced Java interview questions will help you understand the types of questions that will be asked.

In this article, we present the top advanced Java interview questions and answers. We also share some commonly asked interview questions on topics such as multithreading, and OOPs.

Top Advanced Java Interview Questions and Answers

Q1. What is the Function of the intern() Method in Java?

The intern() method in Java is part of the String Class and returns a String if found in the String Pool. If not, a new String is created in the String pool, and the corresponding String’s reference is returned.

Q2. What do You Understand About Garbage Collectors in Java?

This is one of the most common advanced Java interview questions asked in software developer interviews. Garbage collectors in Java are essentially used to free memory space taken up by objects that are no longer in use. An object in Java is rendered non-usable if no thread can access it.

Q3. What do You Understand About JCA in Java?

JCA, or Java Cryptography Architecture, is used by developers to implement security features for a Java application or program. The JCA provides a bunch of application program interfaces that are primarily used for encryption and decryption.

Q4. What do You Understand About Lazy Loading in Java?

Lazy loading is a feature in Java where the loading process of an object is delayed until a thread is ready to use it. Through this feature, a given Java object is initialized only when it is time for it to be used in the program.

Q5. What do You Understand About Eager Loading in Java? How is it Achieved?

Eager loading is a feature by which collections are fetched completely when the parent class is fetched. When a certain query associated with an entity is executed, queries related to similar entities are also executed.

Eager Loading can be achieved using the include() method.

Q6. Explain the Process of Polymorphism in Java?

Polymorphism is a core object-oriented feature in Java where a certain object takes multiple forms. Through this feature, a certain task can be performed in multiple ways. Polymorphism fundamentally occurs when multiple classes are related to each other. Runtime polymorphism and compile time polymorphism are the two ways by which polymorphism is exhibited in Java.

Q7. What do You Understand About Data Abstraction in Java?

Data abstraction is a feature by which the visibility of objects is limited, and only the necessary information or data is visible and accessible to users. The implementation details, which are unnecessary information to users, are hidden through the data abstraction feature.

Q8. What do You Understand About Encapsulation in Java?

This is one of the most popular advanced Java interview questions asked in technical interviews. Encapsulation is a core Java OOPS programming feature where objects and data are bound together into a single unit. By making a class’s data members private, encapsulation is achieved in a program.

Q9. What do You Understand About Class Loading in Java?

Class loading in Java is a feature that enables the data members of a class to load at Runtime. Classloaders are situated in Java.lang package and can be fetched at any time during the program cycle.  Java uses three types of class loaders – bootstrap class loaders, extension class loaders, and systems class loaders.

Q10. What is the Main Disadvantage of Using Garbage Collectors in Java?

This is a common advanced Java interview question asked in technical interviews. As Garbage Collectors constantly monitor objects that aren’t referenced or no longer needed, they run their own thread to free up memory for new objects to be initialized. This increases the load on the system and delays execution. When garbage collectors are used, it becomes difficult to implement mark and sweep.

Below are some additional advanced Java interview questions to help you prepare for your upcoming technical interview:

Advanced Java Interview Questions on Multithreading

1. What do you understand about inter-thread communication in Java?
2. What do you understand about Atomic Action in Java?
3. What are Thread Pooling and ThreadScheduler in Java?
4. What do you understand about the Copy Constructor in Java?
5. What is the function of the finalize() method in Java?
6. What do you understand about Tokens in Java?
7. What are the advantages of Multithreading in Java?
8. Which are the different states in a thread lifecycle?
9. How is thready-safety achieved in Object-Oriented Programming?
10. What are Daemon threads in Java?

Advanced Java Interview Questions on OOPs Concepts

1. What is Association in Java?
2. Explain the concept of Object Cloning in Java
3. Explain Constructor Overloading in Java?
4. What do you understand about the main() method in Java?
5. What is the Marker Interface in Java?
6. What are some differences between Post and Get methods in Java?
7. Differentiate between Runtime and Compile Time Polymorphism
8. What do you understand about Dynamic Method Dispatch in Java?
9. Explain the differences between Abstract Classes and Interfaces in Java.
10. What are the different types of Inheritance in Java?
11. Explain Method Overloading and Method Overriding in Java with a examples

These above advanced Java interview questions will help you prepare for your upcoming software engineering interview.

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FAQs on Advanced Java Interview Questions

Q1. When are Advanced Java Interview Questions Asked in Software Engineer Interviews?

You can expect advanced Java interview questions during the Technical Phone Screen and On-site interviews. In the case of On-site interviews, you’re asked advanced Java interview questions in both coding and systems design rounds.

Q2. Does Java Support the Global Variable Feature Like Some Other OOP Languages?

No, Java doesn’t support the Global Variable feature, mostly because these variables create issues with the Namespace.

Q3. Which are the Core Java OOPs Concepts Around Which Advanced Java Interview Questions are Asked in Technical Interviews?

The core Java OOPs concepts that feature in technical interviews are – Encapsulation, Data Abstraction, Polymorphism, and Inheritance.

Q4. What is Race Condition in Java?

Race condition in Java is a condition wherein two threads raise requests for similar resources to be allocated to execute. Race conditions occur while running two programs parallelly when multiple threads simultaneously request resource allocation.

Q5. What are Some Popular Frameworks Used to Build Java Programs and Applications?

Some popular frameworks used to build Java applications and programs are – React Native, ReactJS, Spring, and Angular. ‍

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