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♥ Converting a BST Tree to a List in Java

This is the reverse of Converting an Array/List to BST in Java. It is a very common task to convert a collection type A to B as a developer. More examples to practice: Converting from A to B There are

Posted in Converting from A to B Tagged with:

♥ ♦ Java coding practice problems – prime and powerful

There is no other way to pass the Java coding tests other than practicing. I have failed Java coding tests due to lack of practice. How often do you get work with tree and graph data structures? Ho often do

Posted in Algorithms, Can you write code? Tagged with: ,

♥ 9 Tips to earn more as a Java developer

Not all jobs and titles are created equal. Why do person “X” and person “Y” performing similar tasks have a difference of 1.2 to 2.0 times in their remunerations? Why do low latency & big data jobs tend to pay

Posted in Earning More Tagged with: ,

♥ Beginner array coding problems in Java

More Data Structure and Algorithms Coding Questions and answers in Java. Q1. Write a program that allows you to create an integer array of 5 elements with the following values: int numbers[ ]={5,2,4,3,1}. The program computes the sum of first

Posted in Array Structure Tagged with: ,

♥ Finding the missing numbers Java example

Q. Can you write code to identify missing numbers in a given array of numbers? Solution 1: Assuming that the given numbers are in order Output: The above solution assumes that the numbers are in order (i.e. sorted). What if

Posted in Can you write code? Tagged with:

♥ Top 10 causes of performance issues in Java

Cause #1: The JVM spends more time performing garbage collection due to improper Garbage Collection (GC) configuration. E.g. Young generation being too small. Heap size is too small (use -Xmx). The application footprint is larger than the allocated heap size.

Posted in FAQs Java Key Areas, Performance Tagged with: , ,

♥♦ Part 1: Badly designed Java classes & interfaces

4 Part practical design concept series Part 1: Abstraction | Part 2: Single Responsibility Principle | Part 3: Open Close Principle | Part 4: Dependency Inversion Principle. Q. Can you review the following code and discuss why they are not

Posted in Designing your classes & interfaces Tagged with: ,

♦ 14+ SQL interview Questions & Answers

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 is the most popular. Q1. Can you explain DDL statements in regards to SQL? A1.…...

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01: ♥♦ Spring DI & IoC interview Q&As

Video: Spring DIP, DI, and IoC. This extends 13 Spring interview questions & answers. Q1. What do you understand by the terms Dependency Inversion Principle (DIP), Dependency Injection (DI) and Inversion of Control (IoC) container? A1. Dependency Inversion Principle (DIP)

Posted in FAQs Free, FAQs Spring, Spring Core Tagged with: , , , ,

01: ♦♥ 17 Java overview interview questions and answers

Q1. Why use Java? A1. One needs to use the best tool for the job, whether that tool is Java or not. When choosing a technology to solve your business problems, you need to consider many factors like development cost,

Posted in Java Overview Tagged with: , , ,

02: ♥♦ Java Compile-time Vs Run-time Interview Q&As

During development and design, one needs to think in terms of compile-time, run-time, and build-time. It will also help you understand the fundamentals better. These are beginner to intermediate level questions. Q1. What is the difference between line A &

Posted in FAQs Free, Java Overview Tagged with: ,

02: ♥♦ Java Generics in no time “? extends” & “? super” explained with a diagram

Generics in Java can be be a bit tricky to get your head around. Hope the explanation below enhances your understanding of generics. This complements 5 Java generics interview Q&As with examples. Plain old List, List <Object>, and List<?> The

Posted in FAQs Free, Generics, Understanding Core Java Tagged with: ,

02: ♥♦ What is wrong with this code? Heap Vs Stack, Thread safety & Synchronized

This post covers must know Java Multithreading basics – Heap Vs Stack, Thread-safety & Synchronization. When you have a multithreaded Java application, you need to code in a thread-safe manner. Java interviewers may ask you to detect thread-safety issues as

Posted in FAQs Free, Multithreading, What is wrong with this code? Tagged with: ,

03: ♥♦ Java autoboxing & unboxing benefits & caveats interview Q&As

Q1. What do you understand by the terms “autoboxing” and “autounboxing” in Java? A1. Java automatically converts a primitive type like “int” into corresponding wrapper object class Integer. This is known as the autoboxing. When it converts a wrapper object

Posted in Data types, FAQs Free, Understanding Core Java Tagged with: ,

06: ♥♦ HashMap & HashSet and how do they internally work? What is a hashing function?

HashMap & HashSet are not only one of the frequently used data structures, but also one of the popular interview topics. Q1. How does a HashMap store data? A1. As key/value pairs. You can store and retrieve values with the

Posted in Collection and Data structures, FAQs Free, Objects, Understanding Core Java Tagged with: ,

Q1-Q10: ♥♦ Top 50+ Core Java Interview Questions and Answers

50+ Core Java interview questions answered for freshers to experienced Java developers. These FAQs have drill down links to more must know Core Java Interview Q&As. Q1. What is the difference between “==” and “equals(…)” in comparing Java String objects?

Posted in FAQs Core Java, FAQs Free, Top 50+ FAQs Core Java Tagged with: , , , ,

Top 6 tips to go about writing loosely coupled Java applications

6 tips to go about writing loosely coupled Java applications useful not only for talking the talk in Java job interviews, but also to build maintainable Java applications. Q1. What is tight coupling? A1. If class OrderServiceImpl relies on parts

Posted in Design Concepts, FAQs Free, Judging Experience Q&As, OOP Tagged with: , , ,

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