Using internal sun classes with javac

Question

Is there a way to disable restrictions of javac 1.6.0_22 that prevent me from using JRE internal classes like sun.awt.event.* ?

I'm not looking for:

1. an explanation why it is forbidden.
2. suggestion to use different classes
3. suggestion to use reflection
4. suggestion to use ecj/eclipse

I just want to know if it is possible or not, and if it is then how.

Answer 1

I have found the answer myself.

When javac is compiling code it doesn't link against rt.jar by default. Instead it uses special symbol file lib/ct.sym with class stubs.

Surprisingly this file contains many but not all of internal sun classes. In my case one of those more-internal-than-usual classes was sun.awt.event.IgnorePaintEvent.

And the answer to my question is: javac -XDignore.symbol.file

That's what javac uses for compiling rt.jar.

Answer 2

In addition to the answer by @marcin-wisnicki if you're using Maven, note that the compiler plugin will silently drop any -XD flags, unless you also specify <fork>true</fork>: e.g.

<build>     <plugins>         <plugin>             <groupId>org.apache.maven.plugins</groupId>             <artifactId>maven-compiler-plugin</artifactId>             <version>3.3</version>             <configuration>                 <source>1.7</source>                 <target>1.7</target>                 <compilerArgs>                     <arg>-XDignore.symbol.file</arg>                 </compilerArgs>                 <fork>true</fork>             </configuration>             ...