Java SE和Java EE中的热交换代理

Question

I found that Hotswapagent works different way in SE and EE application. In SE application I can add a new property to the class (eg private Long x;) without any problem, Hotswap can update the code. But I'm not able to do this in my EE application in a JSF ManagedBean, I got "The virtual machine does not support this operation: schema changes not implemented" .

My EE application is a Maven Enterprise Application (ejb,web,ear projects) in Netbeans 8.2 with Wildfly 10. I use DCEVM (jdk1.8.0_112) and Hotswapagent 1.1.0.

Simple code changes (eg edit method body) are works both in SE and EE applications, but it can't handle new property creation neither in ejb nor in web project. I'd like to know if I made some mistake in settings or this is because the differences between SE and EE environments. Thanks for any ideas.

Answer 1

There's no problem with it. Only when I start application in debug mode.

Answer 2

I would expect the addition of a field to be considered a schema change (in such a case, you would get the exception in both Java SE and Java EE). But Java EE is specific by modification of classes (bytecode) at runtime. I guess that when you inserted a field, it wasn't just that field what was added, but also some synthetic getter and/or setter was introduced, which was a schema change for sure.

Answer 3

HotswapAgent works on JVM level, there should be no difference between Java SE and Java EE. Most probably your Wildfly server does not use DCEVM, please check your setup.

Answer 4

在这里，您需要配置所有EE应用程序服务器Payara + DCEVM的所有配置