Understanding Oracle JDK and OpenJDK: Differences and Similarities

Java is one of the most popular programming languages used for developing a wide range of applications, from mobile apps to enterprise software. At the heart of Java lies the Java Development Kit (JDK), which provides the necessary tools and libraries for building, testing, and running Java programs. Two popular implementations of JDK are Oracle JDK and OpenJDK. In this tutorial, we will explore the differences and similarities between these two JDKs.

Introduction to Oracle JDK and OpenJDK

Oracle JDK is a commercial implementation of JDK developed by Oracle Corporation. It is widely used in enterprise environments due to its stability and long-term support. On the other hand, OpenJDK is an open-source implementation of JDK, which is maintained by the open Java community and Oracle engineers.

Similarities between Oracle JDK and OpenJDK

Both Oracle JDK and OpenJDK are implementations of the same Java specification and have passed the Java Technology Certification Kit (TCK). This means that they provide the same set of APIs, tools, and libraries for building and running Java applications. In fact, Oracle JDK’s build process is based on the OpenJDK source code, with some additional components like the deployment code, Java Plugin, and Java WebStart.

Differences between Oracle JDK and OpenJDK

While both Oracle JDK and OpenJDK are similar in many ways, there are some key differences:

• Licensing: Oracle JDK is licensed under the Oracle Binary Code License Agreement, whereas OpenJDK is released under the GPL v2 license.
• Release Schedule: OpenJDK has a feature release every 6 months, which is only supported until the next feature release. In contrast, Oracle JDK has releases planned every 3 years, with long-term support (LTS) for enterprise environments.
• Additional Components: Oracle JDK includes some additional components like the Java Plugin, Java WebStart, and third-party closed source and open source components like graphics rasterizer and Rhino.
• Font Renderer: OpenJDK uses a different font renderer compared to Oracle JDK.
• Flight Recorder: Oracle JDK has a built-in Flight Recorder, which is not available in OpenJDK.

Choosing between Oracle JDK and OpenJDK

The choice between Oracle JDK and OpenJDK depends on your specific needs and requirements. If you are developing enterprise software that requires long-term support and stability, Oracle JDK may be the better choice. On the other hand, if you are working on a project that requires the latest features and updates, OpenJDK may be more suitable.

Example Use Cases

Here are some example use cases where you might prefer one over the other:

• Enterprise Software Development: Oracle JDK is widely used in enterprise environments due to its stability and long-term support.
• Mobile App Development: OpenJDK is a popular choice for mobile app development, as it provides the latest features and updates.
• Desktop Application Development: Oracle JDK is often preferred for desktop application development, as it includes additional components like the Java Plugin and Java WebStart.

In conclusion, while both Oracle JDK and OpenJDK are implementations of the same Java specification, there are some key differences between them. Understanding these differences can help you choose the right JDK for your specific needs and requirements.

Here is an example code snippet that demonstrates how to use the java.version property to check the version of the JDK:

public class JDKVersion {
    public static void main(String[] args) {
        System.out.println("JDK Version: " + System.getProperty("java.version"));
    }
}

This code can be compiled and run using either Oracle JDK or OpenJDK, and it will print the version of the JDK being used.