[talk] JVM Questions

Pete Wright pete at nomadlogic.org
Wed Mar 19 18:49:33 EDT 2014

On 03/19/14 13:23, Isaac (.ike) Levy wrote:
> Hi All,
> A Java question, for my own sanity.
> Some folks I know are convinced that Oracle JDK and OpenJDK are identical.
> (OpenJDK is our Production standard for many reasons, yet follks keep
> using to Oracle JDK for dev...)

it depends on the JRE you are targeting.  Java8 development is happening
on the OpenJDK side of things first.  I believe the intent is to make it
as performant as the Oracle JRE.  I believe this is also true, to a
lesser extent, with Java 7.

thus spoke the wikipedia:
"The OpenJDK 8 project, which will be the basis for JDK 8, has a planned
release date of 3/18/2014."

> Do folks here know anywhere I can find some practical code examples
> which expose the nasty bugs which can be encountered?
> Do folks here have any such examples, perhaps from your fine Java
> colleagues? (unsigned/signed int mania differences in particular)?
> In the vast and disparate world of Java, is there another good place
> where I should ask to find examples of this stuff?

In my personal experience I found that there rarely are issues running
the OpenJDK as a client system, or even for development.

for example, I use jmxtrans to collect tomcat metrics via JMX at work.
I develop against, and run jmxtrans on freebsd/openjdk6 with out issues.

Although when it comes to production releases we standardize on specific
Oracle JRE's.  This is due to mostly to reduce headaches when working
with external vendors or code-bases that may "require" - kinda how if
you want commercial support from Oracle 11g you need to run either RHEL
or orable linux, not CentOS.  It also removes a variable when trying to
squash hard to pin down bugs.

> I'm dying to get my hands on some code to demonstrate the JVM
> implementation differences, so we can quit focusing on high level
> language spec discussions.

hoping this will be a moot point now that JDK 8 has been released by
Oracle as of Tuesday (March 18th).


Pete Wright
pete at nomadlogic.org
twitter => @nomadlogicLA

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