Point in Lifecycle

Reflective Java

Description

Capabilities

Restrictions

Source Code

Reflective Java [17]

Preprocessor.

Dynamic switching of metaobjects. Intercept method invocations.

Can’t make a compiled class reflective, requires access to source code.

Compile Time

OpenJava [18]

Compile-time metaobject protocol.

Can intercept wide range of operations, and extends language syntax.

Requires access to source code.

Byte Code

Byte code preprocessor (Bean Extender), byte code rewriting as late as load time (Dalang, JavaAssist).

No need to have access to source code.

Bean Extender – restricted to Java Beans. Dalang, and Javassist – limited capabilities. requires offline preprocessing.

Runtime

MetaXa [21], Rjava [22], Guarana [23]

Reflective JVMs.

Can intercept wide range of operations. Can be dynamically applied.

Custom JVM.

java.lang.
reflect [15]

Reflective capabilities part of the standard Java development kit.

Runtime introspection, dynamic dispatch and on-the-fly generation of proxies.

Overall introspection rather than behavioural or structural reflection.

Just-in-time Compilation

OpenJIT [24]

Compile-time metaobject protocol for compilation to machine language.

Can take advantage of facilities present in the native platform. No need for access to source code. Dynamic adaptation.

Custom Just-in-time compiler.