Java进程内存分配 – Memory Areas of Java Process

近日学习到了Java内存管理相关的内容,了解了Java内存中Permanent、Old和Young Generation的概念,内容如下文:
Recently I was learning Java memory management and got some ideas about Permanent, Old and Young Generation concepts, which are mentioned in:

The first chart in the article is useful however it’s in Japanese. I copy a English version with Visio and share it here. The copyright belongs to the  originator and Oracle.

Memory Areas of Java Process

Click to enlarge.


A simple guest book on Google App Engine (Java)

终于算是有些时间,可以试试Google新推出的App Engine的Java语言支持。
Finally got some time to have a trial on Google App Engine – the Java Language.

我下载了Eclipse 3.4.1企业开发版并从更新站点安装了Google插件。在Google插件的帮助下,我在新工程里创建了一个简单的留言簿(GuestBook)模块,并根据文档和范例,写了一个留言(Comment)服务,下面跟用JDO(Java Data Objects)实现的DTO/DAO(Data Transfer/Access Objects)接起来。为了单元测试DAO,还依照GAE官方提供的方法写了JUnit test用的基类来创建App Engine的本地环境。
I’ve downloaded an Eclipse 3.4.1 EE and installed Google Plug-in for Eclipse via the update site. Using the Google Plug-in, I’ve created a GuestBook module, then a Comment service, and a JDO based DTO/DAO for Comment. In addition, I’ve tried out the unit test of a GAE project in local environment.

I’ve got some comments on this first trial, will update in another blog post later.

Anyway, here is the running application hosted on Google’s cloud environment:

源码也在Google Code上边,欢迎朋友们指正:
And the source code is always available here:

For those are trying various Java techniques on GAE, a thread is strongly recommended:

Will It Play in App Engine (or this wiki page)