A Comprehensive Guide to Installing and Configuring OpenJDK 14 on Ubuntu

Java is one of the most popular programming languages used by millions of developers worldwide. The power and versatility of Java has made it the platform of choice for building robust enterprise applications, big data systems, machine learning models, and mobile apps.

At the heart of Java is the Java Development Kit (JDK) – a collection of tools and runtimes that enable you to develop, debug and run Java applications. JDK 14 is the latest long-term support (LTS) release that brings a host of new capabilities for modern application development.

This comprehensive tutorial provides expert guidance on downloading, installing, and configuring OpenJDK 14 on an Ubuntu system. Whether you are setting up your development environment or deploying Java in production, this guide has you covered. Let‘s get started!

An Overview of OpenJDK 14

OpenJDK is the open-source implementation of the Java Development Kit maintained by Oracle and the Java community. Here are some key highlights of JDK 14:

• Language enhancements like record types, pattern matching for instanceof, and helpful null pointers to improve code quality
• Low-latency garbage collection algorithms reduce application lag
• Improved performance and stability across the broader Java ecosystem
• Security updates and hardening of multiple components
• Supports Linux, Windows, and macOS for wide compatibility

You can refer to the official Release Notes for the complete set of changes.

Now let‘s go through the process of getting JDK 14 installed on Ubuntu step-by-step:

Step 1 – Install Pre-requisites

OpenJDK requires some basic developer tools and libraries to be present on your system before installation –

Update System Packages

sudo apt update
sudo apt upgrade -y

This fetches the latest updates from Ubuntu repositories and gets your system up-to-date.

Essential Build Tools

sudo apt install build-essential -y

The build-essential package contains commonly used compilation tools like GCC and Make which are needed.

Graphics Library Dependencies

sudo apt install libx11-dev libxext-dev libxrender-dev libxtst-dev libxt-dev -y

JDK requires X11 libraries to enable graphics and UI functionality. The specific packages enable extensions for rendering and runtime tests.

That completes the pre-requisite setup!

Step 2 – Download JDK 14 Archive

Let‘s pull down ~200 MB compressed JDK archive using curl:

cd /tmp
curl -o openjdk-14_linux-x64_bin.tar.gz https://download.java.net/java/GA/jdk14/076bab302c7b4508975440c56f6cc26a/36/GPL/openjdk-14_linux-x64_bin.tar.gz

We perform the download in /tmp directory to avoid cluttering the root folder.

You should validate the archive integrity by comparing the checksum before we proceed:

sha256 openjdk-14_linux-x64_bin.tar.gz

Which should generate hash:

76bab302c7b4508975440c56f6cc26a99f0a2fbd8f0bff0d6d7c3aedadd59632

Step 3 – Extract JDK Archive

Use tar utility to extract archive contents into /opt/jdk-14 folder:

sudo mkdir /opt/jdk-14
sudo tar xzf openjdk-14_linux-x64_bin.tar.gz -C /opt/jdk-14 --strip-components=1

We consolidate the entire JDK release into a common location instead of having versioned folder like jdk-14.0.1.

Set permissions appropriately:

sudo chown -R root:root /opt/jdk-14/

Step 4 – Set System Environment Variables

In order for OS and other applications to access the JDK, we need to configure a few environment variables:

JAVA_HOME

sudo tee /etc/profile.d/java14.sh <<EOF 
export JAVA_HOME=/opt/jdk-14
export PATH=$PATH:$JAVA_HOME/bin
EOF

JAVA_HOME points to JDK install location while PATH allows execution of Java commands globally.

Source New Variables

source /etc/profile.d/java14.sh

Run the source command to load variables into current shell session.

Step 5 – Verify JDK Installation

With environment set up, verify all is well:

java -version

openjdk version "14" 2020-03-17
OpenJDK Runtime Environment (build 14+36-1461)
OpenJDK 64-Bit Server VM (build 14+36-1461, mixed mode, sharing)

Hooray! We now have JDK 14 properly configured and ready for use.

Some additional validation tests:

Check if JAVA_HOME set:

echo $JAVA_HOME

/opt/jdk-14

List contents of JDK folder:

ls -l /opt/jdk-14

Compile and run sample Java file:

public class Main {
  public static void main(String[] args) {
    System.out.println("JDK 14 Works!");  
  }
}

javac Main.java
java Main

JDK 14 Works!

With Java environment verified, you can now begin developing your applications, tools or frameworks leveraging the powerful capabilities of JDK 14!

Troubleshooting Common JDK Installation Errors

Despite following the instructtions carefully, you may encounter few issues during OpenJDK setup on Ubuntu. Here are some common scenarios and fixes:

Java Not Recognised in Terminal

Error Message:

bash: java: command not found

Problem: PATH variable not updated properly

Solution:

• Check if /etc/profile.d/java14.sh file exists
• Source the file:

source /etc/profile.d/java14.sh

• Retry java command

Zip Extraction Failure

Error:

tar: openjdk-14_linux-x64_bin.tar.gz: Cannot open: No such file or directory

Cause: Incorrect path to archive file

Fix: Verify archive available in current directory before extraction:

ls /tmp/openjdk*
tar xzf /tmp/openjdk-14_linux-x64_bin.tar.gz ...

Installation Folder Permission Issues

Errors like:

No such file or directory
Program can‘t start because libzip.so is missing
Failed to create Java Virtual Machine

Solution: Set open permissions on /opt/jdk-14 folder

sudo chmod -R 777 /opt/jdk-14

I hope this gives you a good overview of troubleshooting basic environment issues during JDK 14 installations. Make sure to check logs at /var/log/ for more details on any errors.

Setting Up a Java Development Environment

Once JDK is installed, let us look at creating a standardized development environment for building Java applications:

1. Install IDEs and Tools

For coding Java, you have the choice of powerful IDEs like:

• Eclipse – Popular open-source IDE. Lean and fast.
• IntelliJ IDEA – Rich features and great tooling. Enterprise grade.
• Apache NetBeans – Free and open-source IDE with drag-n-drop GUI builder.

I would recommend IntelliJ IDEA Community Edition to get started.

Additionally, certain handy tools make programming more productive:

• Maven – Dependency management and build automation tool.
• Lombok – Code generator helping eliminate boilerplate code.

2. Frameworks and Libraries

Some useful frameworks and libraries to learn:

• Spring Framework – Most popular Java framework for building enterprise-grade applications.
• Hibernate – Leading persistence framework to map Java objects to database tables.
• JUnit 5 – Industry standard for unit testing Java applications.
• Log4j – Logging framework to track events during execution.
• Jackson – JSON parsing and processing library for Java.

This forms a good foundation to take on complex Java projects.

3. Sample Applications

Finally, start trying out codes and build some sample apps to get your hands dirty:

• HelloWorld – Basic program to print a line
• Calculator – Arithmetic operations demo
• ToDo Manager – CRUD application with file/database persistence
• Budget Tracker – Spring Boot web application

With the development environment set up, you are ready to build production-grade apps leveraging the powerful Java ecosystem.

Running Java Applications in Production

Here are some best practices to follow when deploying Java applications powered by JDK in production environments – whether self-hosted or cloud:

Optimize JVM Parameters

Tune the heap size, garbage collector algorithms etc. based on app memory requirements and traffic patterns.

Enable Production Mode Flag

Java applications often utilize a development flag that enables hot reloading of code changes. Turn this off in production using:

java -Dspring.profiles.active=production com.app.MainClass

Analyze Performance Statistics

Monitor various metrics like CPU usage, response times, error rates etc. and address any bottlenecks proactively.

Popular APM tools include AppDynamics and New Relic.

Debugging in Production

Use log aggregation tools like Elasticsearch, Logstash and Kibana (aka. ELK stack) to collect application logs across hosts and enable debugging live issues efficiently.

Security Hardening

Follow guidelines for encoding confidential data, input validations, access controls and transport layer encryption mechanisms like SSL/TLS.

Additionally, ensure hosts are hardened against OWASP Top 10 web application threats.

Adoption of these proven methodologies allows your Java applications to keep functioning optimally even under high demand scenarios.

Summary

Java offers an unparalleled ecosystem for building secure, resilient enterprise applications fast – especially with the capabilities unlocked by JDK 14 like records, low-latency GC algorithms and flattened project structure.

This step-by-step guide equipped you to get OpenJDK 14 configured seamlessly on Ubuntu, set up a development environment leveraging tools like Maven and Spring framework, as well as deploy Java apps in production using best practices around performance, security and monitoring.

You now have all the knowledge to start architecting innovative solutions in Java and take advantage of improvements offered by JDK 14!