How to learn Java programming?

December 14, 2019

1. Job focussed
2. What’s the approach?
3. Beginner to Intermediate books
4. Intermediate to Advance books
5. What is the Java Programming Language?

Being a Java software engineer, I’ve often been asked: “What’s a good way of learning Java programming?”
Also, from a career development perspective, I was thinking how I would go about improving my Java and broader programming skills.

What’s the objective?

I think its useful to define some objectives to help target the learning. I think the ultimate goal would be to find a Java programming job. But along the way, it’d be good to develop solid Java skills.

Initial

Learn Core java and increase proficiency
Be confident thinking & programming in Java
Know later versions of Java, eg Java 11, latest Long Term Support (LTS) version
Get to an Intermediate level of Java

Job focussed

Be familiar with Java Test Driven Development (TDD), for improved code quality. Learn about unit tests, integration tests, etc.
Learn a framework (eg Spring) to see how frameworks speed up programming
Learn how to use a build tool (eg Gradle) to easier manage dependencies and build cycle
Write an App to apply knowledge. Put on github for public viewing
Write clean code
Get a Java job

Whats the approach?

Use a good Integrated Development Environment (IDE) and setup your programming environment
1. I like Intellij
2. make sure you can write a ‘Hello World‘ program
Depending on your level: start by reading a good book or doing a good course / watch video
1. start with fundamentals (core java), then syntax, then idioms
2. make sure the book / course has good exercises for each section so you can test your understanding
3. don’t worry about frameworks initially. Start learning the language
As your knowledge grows, keep on coding and thinking in that language
Try to get to an Intermediate level by reading ‘Effective Java‘ and learning Java concurrency
Learn about Test Driven Development (TDD). I appreciate colleagues that write tests to improve code quality
Learn a framework (eg Spring)
Write a Spring Boot Web App in TDD fashion
Do Java tests and practice interview questions
Apply for Java jobs (good luck!)
Contribute to Open Source projects and help the community

Beginner to Intermediate books

Java: A Step-by-Step Guide for Absolute Beginners (Bell, 2019)
Beginning Programming with Java For Dummies 5th Ed (Burd, 2017)
Learn Java in One Day and Learn It Well (Chan, 2016)
Thinking in Java 4th Ed (Eckel, 2006)
Core Java Volume 1 – Fundamentals, 11th Ed (Horstmann, 2018): updated to Java SE 9, 10, 11
Core Java SE 9 for the Impatient 2nd Ed (Horstmann, 2017)
Head First Java 2nd Ed (Sierra, Bates, 2005): good but dated, only up to Java SE 5
Test Driven: TDD and Acceptance TDD for Java Developers (Koskela, 2007)

Intermediate to Advance books

Effective Java 3rd Ed (Bloch, 2017): updated to Java SE 7, 8, 9
Java Concurrency in Practise 1st Ed (Goetz, 2006)
Clean Code: A Handbook of Agile Software Craftsmanship 1st Ed (Martin, 2008)
Java Performance: The Definitive Guide 1st Ed (Oaks, 2014): garbage collection, JVM, performance tuning
Reactive Programming with RxJava (Nurkiewicz, 2016)

What is the Java Programming Language?

Java is a programming language that is strongly typed, Object Oriented and imperative. It has a philosophy of Write Once, Run Anywhere (WORA).

Principles

It must be simple, object-oriented, and familiar.
It must be robust and secure.
It must be architecture-neutral and portable.
It must execute with high performance.
It must be interpreted, threaded, and dynamic.

Pros

robust & standard for enterprise computing
good performance, multi threaded
fewer security risks
platform independent (WORA)
Object Oriented (OO) programming (improved over procedural programming)
very popular: lots of java engineers, and lots of java jobs
big and mature community, lots of open source libraries

Cons

paid commercial license
large memory footprint
verbose (compared to Kotlin)
no functional programming
desktop is far from native look & feel