The Oracle Add-in uses a mechanism for supporting multiple Java environments (Oracle Plug-in, JInitiator) and their versions (JInitiator 1.1.8, 1.3.1, and so on) without requiring any configuration changes. This mechanism is known as dynamic transformation support.
Dynamic transformation support uses the profiler interface of the Java Virtual Machine (JVM) to adjust the Oracle Add-in support classes according to the Java environment and version in use.
The dynamic transformation support mechanism is invoked by the _classload_hook=jvmhook option (for JInitiator 1.1.x) supplied to the JVM. If this option is specified, the JVM hook profiler, which is part of the Oracle Add-in support, is loaded with every application or applet and dynamically transforms the necessary classes to enable context-sensitive Oracle support.
If the dynamic transformation support mechanism does not work properly, you can disable it and manually configure the Oracle environment to use the Oracle Add-in without dynamic transformation support. For details, see Disable Dynamic Transformation support.
The dynamic transformation support mechanism is not supported when using the incremental garbage collector (-Xincgc option). Therefore, if you absolutely must use the -Xincgc option, you need to disable dynamic transformation support. For details, see Disable Dynamic Transformation support