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♦ 3 Java class loading interview Q&As to ascertain your depth of Java knowledge

Q1. What do you know about Java class loading? Explain Java class loaders? A1. Class loaders are hierarchical. Classes are introduced into the JVM as they are referenced by name in a class that is already running in the JVM. So, how is the very first class loaded? … Read...

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♦ Java classes and interfaces are the building blocks

Q1. Which class declaration is correct if A and B are classes and C and D are interfaces? a) class Z extends A implements C, D{} b) class Z extends A,B implements D {} c) class Z extends C implements A,B {} d) class Z extends C,D implements B {}...

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00: 15+ Java multi-threading interview Q&As

Even the experienced Java developers dread Java multithreading interview questions & coding exercises. Interviewers love to drill you on multithreading as it can reveal a lot about your capabilities.

Q1. What is a thread?
A1. It is a thread of execution in a program.

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00: 17 beginner Java interview questions and answers

These 17 beginner Java interview questions & answers are not only for the entry level job interviews, but also get a good grasp of the beginner level Java concepts.

Q1. Why use Java?
A1. Java is a very popular language as per the TIOBE index.

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01: 12 Web basics every Java web developer must know

Q1. HTTP is a stateless protocol, so how do you maintain state? How do you store user data between requests?
A1. This is a commonly asked interview question. The “http protocol is a stateless request/response based protocol”. You can retain the state information between different page requests as follows:

HTTP Session.

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02: 10 Java String class interview Q&As

Java Collection interview questions and answers and Java String class interview questions and answers are must know for any Java developer as these two APIs are the most frequently used in your Java application code. You can’t write any decent Java application without these 2 APIs.

Q1.

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03: ♦ 12 Java Generics interview Q&As

Q1 What do you understand by the term type erasure with regards to generics? A1. The term type erasure is used in Java generics. In the interest of backward compatibility, robustness of generics has been sacrificed through type erasure. Type erasure takes place at compile-time. … Read more ›...

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03: ♦ 21+ Java Servlet interview Q&As

Q1. What is a Servlet? Is a Servlet inherently multi-threaded? A1. A Servlet is a Java class that runs within a web container in an application server, servicing multiple client requests concurrently forwarded through the server and the web container. The web browser establishes a socket connection to the host...

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03: 9 Core Java Concepts you can’t afford to not know

Q1. How will you go about explaining the following Java concepts to a beginner who is starting to learn Java? 1. Process Vs Threads 2. Heap versus Stack 3. Local variables versus instance variables 4. How do threads communicate with each other? 5. … Read more ›...

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04: Top 10 most common Core Java beginner mistakes

Mistake #1: Using floating point data types like float or double for monetary calculations. This can lead to rounding issues. In the above code, 2, 4, and 5 are correct and 1 and 3 are incorrect usage leading to rounding issues. … Read more ›...

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14+ SQL interview Q&As

SQL interview Questions & Answers is a must for any developer as all non-trivial applications need to talk to a database with CRUD operations. Q3 – Q15 are very popular with the interviewers. If you want to quickly practice your SQL skills try DB Fiddle or install MySQL locally as shown in the ⏯ MySQL database beginner video tutorial.

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15 Database design interview Q&As

Q1. What is normalization? When to denormalize? A1. Normalization is a design technique that is widely used as a guide in designing relational databases. Normalization is essentially a two step process that puts data into tabular form by removing repeating groups and then removes duplicated data from the relational tables....

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4 more Java EE overview interview questions and answers

Q1. How does the new bean validation framework avoid duplication across multiple Java EE layers? A1. Developers often code the same validation logic in multiple layers of an application, which is time consuming and error-prone. At times they put the validation logic in their data model, … Read more ›...

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5 Java Object class methods interview questions & answers

Q1. What are the non-final methods in Java Object class, which are meant primarily for extension? A1. The non-final methods are equals( ), hashCode( ), toString( ), clone( ), and finalize( ). These methods are meant to be overridden. … Read more ›...

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6 Java Modifiers every interviewer likes

Java modifiers like final, finally, const, volatile, transient and finalize are very popular with the job interviewers. You will see why because of the possible drill down questions.

Q1. What is the difference between ‘final‘ and ‘const

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8 Java immutable objects interview questions & answers

Best Practice: “Classes should be immutable unless there’s a very good reason to make them mutable….If a class cannot be made immutable, limit its mutability as much as possible.” — by Joshua Bloch Q1. What is an immutable object? Q2. Immutable objects are objects whose state (the object’s data) cannot...

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8 JEE (i.e. Java EE) Overview interview Q&As

This is JEE from a 10,000 feet before diving into details of each technology.

Q1. When a company requires Java EE experience, what are they really asking for?
A1. Java EE (i.e. Enterprise Edition) is a collection of specifications for developing and deploying enterprise applications.

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9 Java Garbage Collection interview questions & answers to ascertain your depth of Java knowledge

Java Garbage Collection interview questions & answers to ascertain your depth of Java knowledge in building industry strength Java applications.

Q1. In which part of memory does Java garbage collection (i.e. GC) occur? When does the garbage collection occur? In which thread does the GC run?

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Java 7: Top 8 new features with examples

There are several small new features and enhancements in Java 7. The major features and enhancements are in Java 8. Let’s look at the Java 7 new features. #1: string in switch statement: Output is: #2 Binary integral literals Output: #3: Underscores for better readability in numeric literals Output: #4:...

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Java serialization, cloning, and casting interview Q&A

Q1. Which Java interface must be implemented by a class whose instances are transported via a Web service? a. Accessible b. BeanInfo c. Remote d. Serializable A1. Answer is “d”. Q2. What is serialization? A2. … Read more ›...

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Object equals Vs == and pass by reference Vs value

Q1. What is the difference between “==” and equals(..) method when comparing 2 objects?
A1.It is important to understand the difference between identity (i.e. ==) comparison, which is a shallow comparison that compares only the object references, and the equals( ) comparison,

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Q1-Q10: Top 50+ Core Java interview Q&As

These are must know Java interview FAQs. If you don’t get these Java interview questions right, you will not be getting an offer.

Q1. What is the difference between “==” and “equals(…)” in comparing Java String objects?
A1. When you use “==” (i.e.

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Q11-Q23: Top 50+ Core Java Interview Q&As

The focus is on Java OOP interview questions and answers. Q11. What is the difference between constructors and other regular methods? A11. Constructors must have the same name as the class name and cannot return a value. The constructors are called only once per creation of an object while regular...

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Q24-Q36: Top 50+ Core Java interview Q&As

Focus is on Java classes, interfaces and generics the interview questions and answers style. Java classes and interfaces are the building blocks. Q24. What happens when a parent and a child class have the same variable name? A24. … Read more ›...

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Q37-Q42: Top 50+ Core Java Interview Q&As

As a Java developer, you may not need to know how the JVM works, but the most important topic that you must know is Java Garbage Collection. How the Garbage Collection and object referencing work in Java. Q37. What do you know about the Java garbage collector? … Read more...

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Q43-Q54: Top 50+ Core Java Interview Q&As

Q43. What can you tell about the performance of a HashMap compared to a TreeMap? Which one would you prefer? A43. A balanced tree does have O (log n) performance. The TreeMap class in Java maintains key/value objects in a sorted order by using a red-black tree. … Read more...

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