Introduction to the Programming in Java 👨🏫
This is a pillar post containing links to articles including Java code examples are focused on helping beginner through advanced software developers learn how to program in Java in a step-by-step manner.
In these guides I focus on finding questions that people are asking about regarding specific aspects of the Java Programming Language and I engineer the content with that in mind.
Introduction to Java TOC
This article was updated on March 21, 2025.
Prerequisites
Most of these articles include links to existing scripts available TIO.run which the beginner software engineer can execute via their browser.
Oracle Java or OpenJDK will be required to run these examples locally.
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Tutorial (beginner level): Exploring the ArrayList constructor in Java for Array-to-List Conversion 
The instructional details how to use the Java ArrayList constructor in Java to convert an array into a mutable ArrayList.
Tutorial (beginner level): Arrays.asList code example for immutable lists 🤔
This step-by-step guide is designed to help the beginner Java programmer understand how to use the Arrays.asList method to convert an array to a fixed-size immutable List.
Tutorial (beginner level): Java Stream to ArrayList explained in five easy steps! 
This walkthrough explains in detail how to convert data using Java Stream to an Array List in your project.
Tutorial (beginner level): Use Guava Lists class to convert an array into an ArrayList!
This step-by-step walkthrough explains how to use the Google Guava library’s Lists.newArrayList method to convert an array to an ArrayList in Java.
Article (intermediate level): Is autoboxing in Java wrecking your application performance?
This article explores the implications of Java autoboxing on application performance, a feature that automatically converts between primitive types and their corresponding wrapper classes.
Tutorial (advanced level): Learn how to access the H2 DB console from a browser!
This guide provides software developers with instructions regarding how to embed the h2 database in your Java application as well as how to access the embedded H2-console from a browser.
Tutorial (beginner): Learn how to add an element to a List in Java! 
This article provides a detailed guide on the Java List add method, and also explains how to add elements at specific positions, and add multiple elements from other collections.
Tutorial (beginner): Learn how to convert an array to an ArrayList in Java! 
This article provides a guide regarding how to turn an array into an ArrayList, and details the entire process with clear, step-by-step instructions with example code and explanations.
Tutorial (advanced): Learn how to use the h2 database in Spring Boot! 
This step-by-step guide provides an example regarding how to configure the h2 database with Spring Boot and includes an example which is written in the Groovy scripting language and which demonstrates several CRUD operations.
Tutorial (advanced): Learn how to implement Oracle Database Change Notifications by example!
The instructional covers how to use Oracle Data Change Notifications (Oracle DCN) to monitor for changes in a database, detailing the setup process, benefits, and specific use cases for software engineers to efficiently track and respond to data modifications in real-time.
Tutorial (advanced): Learn how to listen for table changes in PostgreSQL in seven steps!
This guide explains how to subscribe to changes in the Postgres database using pg_notify, how to create a trigger function to monitor table changes in Postgres, how to implement a PGNotificationListener interface to handle notifications, and how to configure the connection via the Impossibl JDBC driver; an example, written in the Groovy Programming Language (Groovy), is also provided.
Learn how to code a simple Jedis PubSub Client for Redis now!
This Jedis tutorial demonstrates how to implement a simple Redis client using Jedis PubSub functionality in the Groovy scripting language in three easy steps.
This article details the steps of creating a publish/subscribe messaging system in Redis, using the Jedis subscribe functionality to handle real-time updates.
Tutorial (advanced): Learn how to use Postgres with Spring Boot!
This Groovy script example explains how to connect a simple Spring Boot application with the PostgreSQL database and then perform several create, read, update, and delete (CRUD) operations.
Article Conclusion
See the Java code examples category for other instructionals geared towards both beginner and advanced software engineers.
