Q1. Are annotations a compile time or run-time feature? A1. You can have either compile-time or run-time annotations. @Override is a simple compile-time annotation to catch little mistakes like typing tostring( ) instead of toString( ) in a subclass. … Read more ›...
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...
Java Garbage Collection interview questions & answers to ascertain your depth of Java knowledge in building industry strength Java applications. Determining optimal Garbage Collection (GC) settings is critical to achieve high throughput & low latency.
Q1. In which part of memory does Java Garbage Collection (i.e.
…
#1. Why convert a Date to String & a String back to Date
(a) Convert a String input from say a file date, so that you can perform operations like
1) Adding 5 days to the date.
2) Comparing a date like before,
…
#1. Does Java have a “Money” class? No. This will change in Java 9 with the “Money API”. JSR 354 defines a new Java API for working with Money and Currencies. #2. What are the 2 potential pitfalls in working with money? … Read more ›...
This post is for quick brush-up. These Q&A are discussed in detailed elsewhere in posts like Java modifiers interview Q&A | Java generics interview Q&A | Java annotations interview Q&A Q1. What are the differences among final, finally, and finalize? … Read more ›...
This is a good candidate to make it to the job interview discussions along the debate of checked Vs unchecked exceptions as the industry is split on this very topic. Some favor XML, whilst others love using the JavaConfig. Q1. What are the Pros and Cons of Spring JavaConfig Vs....
Event Driven Architecture aka EDA loosely couples event producers and event consumers. An event can be defined as “a change in state”. For example, when an event producer fires an event to notify all its registered listeners that either “securities” or “security prices” have been loaded, … Read more ›...
This extends the basic tutorial on event driven programming in Java. This tutorial covers JMX enabling the EventHub class vian MBeans and monitoring through JMX compliant tool like jconsole. Step 1: Define the interface with the methods that are intractable via the JMX compliant client like jconsole. … Read more...
Complimenting Fibonacci number coding – iterative and recursive approach, we can improve performance by caching. If you run this
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
public class RecursiveFibonacci { public int fibonacci(int n) { if (n == 0 || n == 1) return n; System.out.println("evaluating fibonacci(" + n + ")"); return fibonacci(n - 2) + fibonacci(n - 1); } public static void main(String[] args) { int nThfibonacciNo = new RecursiveFibonacci().fibonacci(5); System.out.println(nThfibonacciNo); } } |
Output
|
1 2 3 4 5 6 7 8 9 |
evaluating fibonacci(5) evaluating fibonacci(3) evaluating fibonacci(2) evaluating fibonacci(4) evaluating fibonacci(2) evaluating fibonacci(3) evaluating fibonacci(2) 5 |
and you can see “fibonacci(3)” is repeated 2 times, “fibonacci(2)” is repeated 3 times, and so on. If you pick a larger number like 21, … Read more...
UUID stands for Universally Unique ID. A UUID is known in the Microsoft world as as a GUID.
What does a UUID look like?
The UUID is not a string, but a 128-bit value. The UUID is a hexadecimal value like
|
1 |
4536ca53-bcad-4552-977f-16945fee13e1 |
How to generate a UUID in Java?…
Performing impact analysis is a crucial software development task. It is all about calculating the impact of software change.
Q1. What is an impact analysis? Is it a trivial task?
A1. An impact analysis is about being able to tell which pieces of code,
…
This post answers questions like — How to write internationalized Java applications? What do you understand by the terms internationalization (i18n) and localization (l10n) relating to Java programming? What is a ResourceBundle?
Localization (aka i10n, where 10 is the number of letters between the letter ‘i’ and the letter ‘n’ in the word localization ) refers to the adaptation of an application or a component to meet the language,
…
I have a good news, I got job offer. I like to share with you from my bottom of my heart feeling thankful to you.