anchor.diff:  The Graal SDK supports substitutions of classes in the native image. An example of how one could replace the `XmlConfig/XmlData` classes with versions that have no JAXB annotation dependencies is shown in these example classes:
   
   .Substitution of XmlConfig/XmlData Classes Example
  -[source,bash]
  +[source,java]
   ----
   package io.quarkus.extest.runtime.graal;
  -
   import java.util.Date;
  -
   import com.oracle.svm.core.annotate.Substitute;
   import com.oracle.svm.core.annotate.TargetClass;
  -
   import io.quarkus.extest.runtime.config.XmlData;
  +
   @TargetClass(XmlConfig.class)
   @Substitute
  -final public class Target_XmlConfig {
  +public final class Target_XmlConfig {
  +
       @Substitute
       private String address;
       @Substitute
  
positive.code: ./mvnw clean install -Dquarkus.debug.generated-classes-dir=./target/app-generated-classes
  ----
  
  
  === Sample Test Extension
  We have an extension that is used to test for regressions in the extension processing. It is located in {quarkus-tree-url}/core/test-extension directory. In this section we touch on some of the tasks an extension
  
negative.code: 
  @TargetClass(XmlData.class)
  @Substitute
  public final class Target_XmlData {
  
      @Substitute
      private String name;
      @Substitute
  