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Wonseok Kim

Wonseok Kim is a senior developer at TmaxSoft, South Korea. He works on the development of Tmax Application Server - very popular in Korea. He has been participated in JCP such as JSR 244 (Java EE 5) and JSR 220 (EJB 3.0). He is also a contributor to GlassFish project. Prior to Java EE he had developed NMS and OSS systems for telecommunications in Java. Now he has concerns primarily on EJB and persistence technologies and is working on them.


guruwons's blog

Java EE 6: module and application scopes of java:comp/env?

Posted by guruwons on June 5, 2008 at 8:47 PM PDT

I would like to get feedbacks about
application-scoped and module-scoped resource/EJB references (in
java:comp/env) which are being discussed in Java EE 6 JSR.

As you know, when we define simple
environment entries or refer to data sources or EJBs we need to
specify java:comp/env ENC(Environment Naming Context) entries like


EclipseLink sessions in 2008 JavaOne

Posted by guruwons on April 28, 2008 at 10:18 AM PDT

I plan to attend JavaOne this year again.

TopLink Essentials enhancements - category-specific logging level and cascade refresh query hint

Posted by guruwons on July 6, 2007 at 7:39 PM PDT

Recently I've implemented two minor but useful features for TopLink Essentials(TLE) v2 b54(or GlassFish v2 b54).

TopLink Essentials 2.0 and maven repository

Posted by guruwons on February 17, 2007 at 2:37 AM PST

TopLink Essentials 2.0?

TopLink Essentials(GlassFish JPA implementation) now come to have a new
version 2.0. But, don't be surprised, this is just versioning change from 9.1.
TopLink Essentials 2.0 and 9.1 are the same version.

Originally TopLink Essentials had a version like 9.0(GlassFish v1),
9.1(GlassFish v2) after the version of Sun Java System Application

Sending large files over JMS

Posted by guruwons on November 15, 2006 at 8:30 AM PST

JMS provides powerful asynchronous communication, but it is message-oriented and doesn't support InputStream/OutputStream at all. So it is nearly impossible to send a large file without loading it on memory. How can we acheive this? Let me talk an enhancement of JMS for this issue.

JPA: Supplement to the access type of @Embeddable class

Posted by guruwons on October 16, 2006 at 8:11 AM PDT

In Java Persistence API, Embeddable class is used to represent composite primary key or share common columns between entities. But when sharing Embeddable classes, you should be cautious whether its fields or properties are mapped to the database due to the unclear spec. I will introduce the supplementary rules to the spec which is implemented in GlassFish(TopLink Essentials).

How to configure a logger type in TopLink Essentials (Part 2)

Posted by guruwons on September 22, 2006 at 1:29 AM PDT

Previously I bloged about How to use Java Logger in Java SE mode - a workaround to change logger type. But the workaround is no more needed.

Understanding the cache of TopLink Essentials(GlassFish JPA)

Posted by guruwons on September 7, 2006 at 8:38 PM PDT


The hype of JPA has slowed down and time has come to apply this to real applications.

TopLink Essentials: How to use Java Logger in Java SE mode

Posted by guruwons on September 6, 2006 at 4:06 AM PDT

TopLink Essentials(GlassFish JPA RI) can be used also in Java SE mode as you know. I will talk about how to change the default logger to java logger in this article.

When you use TopLink in Java SE, you see following log messages generated by a default logger.

EJB 3 & JPA material used in JavaOne wrapup seminar held in Seoul

Posted by guruwons on July 10, 2006 at 6:28 PM PDT

So many people came to JavaOne wrapup seminar held in Seoul, Korea on 8 July. It was organized as small scale(100 people expected) by Sun Korea, but I guess more than 200 people came in.