[talk] JVM Questions

[Sujit K M]

On Thu, Mar 20, 2014 at 1:53 AM, Isaac (.ike) Levy
<ike at blackskyresearch.net> 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...)

Might be the compilers they use might sun studio for Oracle JDK and GCC for
OpenJDK.

> QUESTIONS:
>
> Do folks here know anywhere I can find some practical code examples which
> expose the nasty bugs which can be encountered?

The ODBC/JDBC Drivers are particular to these. One bug I find and keep finding
is the one below
          resultSet.getInt(getParameter()); // will most probably lead
to a very bad bug
           resultSet.get(i);// is not going to get this.

> 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?

One of the major bugs I found in the Collections Framework was the HashMap
and ConcurrenAccessException in JDK5 long time ago. I Think Best way
to Look at this is in Exceptions that a method or class instance might throw
and try writing a unit test case for that.

>
> 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.

Best way would be to compile OpenJDK using Sun Studio and seeing
how it goes from there.