Is the OpenJDK JVM the same as the Oracle Java SE JVM?

Question

I understand that the Oracle Java SE contains closed source extensions and tools that are not part of the OpenJDK however is the Oracle Java SE JVM identical to the OpenJDK JVM or does Oracle make changes to the OpenJDK JVM before releasing it as a Java SE JVM?

Update 1: I found some info from the JDK7 updates projects: http://openjdk.java.net/projects/jdk7u/qanda.html

Will the 7 Update Project receive security fixes from Oracle?

Yes.

As with OpenJDK 6, security fixes are first kept confidential and applied to a private forest before being pushed to the public forest as part of the general synchronized publication of the fix to effected JDK release trains. In addition, they will not go through the public code review and putback approval process, and their corresponding issues in the Project's issue tracker will not be publicly visible.

Solution

OpenJDK is the reference implementation of Java as of version 7.

OpenJDK 7 is the starting point for the version that Oracle distributes as Oracle JDK. Other vendors (e.g. RedHat for IcedTea) may also use OpenJDK as their starting point.

In terms of the differences between OpenJDK and a vendor VM, there may be patches which a vendor wants to apply but which the overall OpenJDK community has not accepted into mainline.

Vendor VMs must, of course, be able to prove that they are in conformance with the TCK if they want to use the Java trademarks to describe their product.

Oracle JDK is also not open-source. This is possible because of Java's dual licensing arrangements, and the fact that Oracle own Java overall.

Do you have more specific questions - as posed, your question is a bit vague. What specific aspects are you interested in?

Comments

[yazz.com]

I didn't understand this answer. So is the JVM the same. yes or no?

[kittylyst]

What do you mean - precisely - by "is the same as"? Quick clue: This probably isn't as straightforward a question as you may think.

[Zsolt]

Do you happen to know what happens to a security fix? I saw that oracle fixed something in jdk8 however I was unable to find the matching fix in openjdk 8u

[kittylyst]

@Zsolt All security fixes present in Oracle JDK 8 will also arrive in OpenJDK 8 - but Oracle release first, as some bugs are kept confidential. For serious issues, OpenJDK follows within days. E.g. for the recent 8u212 release, AdoptOpenJDK was at parity with OpenJDK within 2-3 days. Do you have a specific issue you're concerned with?