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01: 19 Java 8 Functional Programming FAQs

Good handle on Java OOP concepts and FP concepts are very important NOT only from writing quality code perspective, but also from job interviews perspective to be able to do well in written tests & technical interviews.

Q1. Can you explain your understanding of Functional Programming (FP)?

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01: 7 rules to remember on Java Generics for better understanding

Here are 7 rules to remember regarding Java Generics to understand Generics and handle interview and coding questions on Core Java. Object <– Fruit <– (Orange, Mango, etc siblings) Rule 1: Java generics differ from C++ templates. Java generics (at least until JDK 8), … Read more ›...

01: Java data types interview Q&A

Q1. How would you go about choosing the right data types for your application? A1. Java is what is known as a strongly typed language. This means Java only accepts specific values within specific variables or parameters. Some languages, such as JavaScript, PHP, … Read more ›...

01: jvisualvm tutorial to sample Java heap memory

Java does not have a sizeof operator like C++ does. Java uses automatic memory management known as the Garbage Collection, hence it is not that important to evaluate size of various objects. But, for the purpose of learning & fixing any potential memory issues, I have used “jvisualvm”, … Read...

01: OOP vs FP with Java example – placing a trade

A Trade goes through 3 state changes – placed, filled, and settled. Let’s solve this simple problem using both OOP & FP approaches.

Place –> Fill –> Settle

OOP approach by mutating the state

State changes are maintained via a variable named “

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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. … Read more...

02: 5 Java multithreading scenarios interview

Java interview questions & answers on multithreading scenarios to judge your experience in building applications with concurrency in mind. Q1. Can you give some scenarios where you built concurrent systems? A1. In a concurrent system different threads run concurrently, … Read more ›...

02: 9 Java Collection interview Q&As on choosing the right data structure

Choosing the right data structure is vital to get the job done with proper space vs performance trade-offs. Q1. What are the common data structures, and where would you use them? A1. Deterministic Data Structures like Arrays, … Read more ›...

02: Java 8 Streams, lambdas, intermediate vs terminal ops, and lazy loading with simple examples

A stream is an infinite sequence of consumable elements (i.e a data structure) for the consumption of an operation or iteration. Any Collection<T> can be exposed as a stream. It looks complex, but once you get it, it is very simple. The operations you perform on a stream can either...

02: jvisualvm to detect memory leak – a quick tutorial style Java demo

This is a companion post to 8 Java Memory Management Interview Q&A demonstrating a memory leak scenario step by step with jvisualvm, which is a free profiling tool that gets shipped with JDK. Step 1: Code that causes memory leak Here is a sample code that causes memory leak. …...

02: OOP vs FP with Java example – Conversion strategy pattern

Java code to convert given input values from KM to Meter, Meter to Centimetres, etc. OOP approach using the strategy design pattern Step 1: Define an interface. Step 2: Define a generic “MyMetricConverter” that implements the “Converter”. Step 3: Define different strategy classes that return different conversion rates. … Read...

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 ›...

03: 7 Things you must know about Java locks and synchronized key word

7 Things you must know about Java locks and synchronized key word summarizes the key basics. #1. Each Java class and object (i.e. instance of a class) has an intrinsic lock or monitor. Don’t confuse this with explicit lock utility class that were added in Java 1.5, … Read more...

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800+ Java Q&As & tutorials