Java-is-OpenJDK-is-Java

See this to learn what OpenJDK is about, and the ecosystem around it (including Oracle)
http://www.redhat.com/summit/2012/pdf/2012-DevDay-OpenJDK-Bhole.pdf‎

It all began in 2006, when Sun Microsystems started releasing Java as free,open source software (FOSS)
under the GPL 2.0 license*
https://today.java.net/pub/a/today/2006/11/13/open-source-java-editorial.html …

IBM Joins OpenJDK
http://www.sutor.com/c/2010/10/ibm-joins-the-openjdk-community/

SAP joins OpenJDK
http://scn.sap.com/community/open-source/blog/2011/07/14/sap-joins-openjdk

AMD and Oracle team up for Java GPU acceleration
http://www.eweek.com/developer/amd-oracle-team-for-openjdk-sumatra-java-gpu-project/

Apple and Oracle announce OpenJDK for Mac OS X
http://www.apple.com/pr/library/2010/11/12Oracle-and-Apple-Announce-OpenJDK-Project-for-Mac-OS-X.html

Oracle makes OpenJDK the Java7 reference implementaiton
http://www.infoq.com/news/2011/06/openjdk-bylaws

Oracle open sources JavaFX 2.0 as OpenJFX under GPL license
http://openjdk.java.net/projects/openjfx/

Q: So, is the code the same?
Answer: in Java 6 vs OpenJDK 6 there were more differences, but in Java 7 / OpenJDK 7 those were narrowed
see http://stackoverflow.com/questions/8705061/is-the-openjdk-jvm-the-same-as-the-oracle-java-se-jvm
… see also slide #3 of http://www.redhat.com/summit/2012/pdf/2012-DevDay-OpenJDK-Bhole.pdf
… "95% shared code" in OJDK7 (RedHat Claim)

The browser plug-in component was never open sourced by Sun Microsystems. That is provided in the FOSS OpenJDK project by the "Icedtea-web" component, developed mostly by RedHat. Icedtea-web also includes the JWS (Java Web Start) implementation in addition to the browser plug-in.

======JAVA 8============
Oracle open sources JavaFX 2.0 for iOS and Android
http://www.infoq.com/news/2013/02/javafx-ios-android

Oracle releases Nashorn, the next'generation Javascript engine for the
Java VM in Java8 and OpenJDK 8
http://www.dzone.com/links/all_about_oracle_nashorn_the_nextgeneration_javas.html

OpenJDK 8, Java 8 Reference Implementation
https://jdk8.java.net/java-se-8-ri/

"JDK 8 was developed collaboratively in the OpenJDK Community..."
http://www.oracle.com/us/corporate/press/2172618
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Notes:
* Java was released as GPL 2.0 with the "Classpath exception",
so executables created by its compiler can be exempt from the GPL, ie
you can use OpenJDK javac compiler to create non-free software, if you wish so.