The Java ecosystem is incredibly diverse.  It powers billions of devices and servers. It is key to cloud infrastructure worldwide. Even just the Java Platform, Standard Edition, “Java SE”, which is the core Java platform for general computing, is itself diverse.

We on the Java Platform Group at Oracle think of our work on “Java SE” in four main areas, described below.

1) OpenJDK.  OpenJDK is the place we collaborate on an open-source implementation of the Java Platform, Standard Edition, and related projects.  Our commitment to OpenJDK remains as strong as ever and we even recently kicked off the JDK 10 project there. OpenJDK enjoys broad participation across the ecosystem. It has consistently grown in activity since Oracle acquired Sun.  For example, most major Linux distributors and other parties such as Red Hat, Canonical and SUSE produce and ship binaries based on this opensource code.  The source code is available under the popular GNU General Public License v2, i.e. it's completely gratis. Commercial source licenses are also available for companies that would like to license the source code for a multitude of purposes, and dozens have, such as HP, SAP, IBM and others who produce their own commercial Hardware/OS products for which they'd like to have a commercial grade Java SE port available.

2) Oracle's Java SE implementation, aka "Oracle JDK" and "Oracle JRE".  The Oracle JRE/JDK is Oracle's implementation of Java SE.  Just as many other companies (like SAP, Red Hat, IBM, HP, etc) provide their implementations of Java SE to their customers, so does Oracle.  We have two main channels for our binary distributions -- java.com is for consumers who may want to run the Java Runtime Environment (JRE) on their home computers for applications like Minecraft or other Java based consumer software, and the Java Development Kit (JDK) on OTN which is targeted to developers and enterprises.  These binaries are gratis for the vast majority of use cases as noted in java.com/license.

 3) Oracle Java SE Advanced, Java SE Advanced Desktop, Java SE Suite.  In addition to Oracle's core Java SE implementation, Oracle also provides additional advanced tools and features that target enterprise users.  These features include the tools to help monitor, manage and deploy Java within an enterprise, advanced runtime diagnostics and monitoring, as well as access to support and updates to legacy versions of Java SE such as Java SE 6, and Java SE 7. These commercial features are provided as separate downloads available via “My Oracle Support” or OTN, and to the degree they need to interact with the Oracle JRE, they are turned off by default in that product, and can be enabled using the "-XX:+UnlockCommercialFeatures" flag at runtime in your JVM, for example. More information on specific commercial features can be found in Table 1-1 here.

 4) Java SE embedded.  As noted in (2), the Oracle JRE/JDK is gratis for most use cases, where it is running on a General Purpose desktop or server.  If a customer would like to embed the Oracle JDK/JRE in a device of some kind (eg, a cash register) then the gratis BCL license does not apply. In such cases a commercial Java SE embedded license needs to be negotiated. Java SE embedded also provides additional binary options for resource constrained devices and more embedded oriented chip sets.