src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.api.replacements/src/org/graalvm/compiler/api/replacements/ClassSubstitution.java

*** 55,63 ****
       */
      String[] className() default {};
  
      /**
       * Determines if the substitutions are for classes that may not be part of the runtime.
!      * Substitutions for such classes are omitted if the original classes cannot be found.
       */
      boolean optional() default false;
  }
--- 55,65 ----
       */
      String[] className() default {};
  
      /**
       * Determines if the substitutions are for classes that may not be part of the runtime.
!      * Substitutions for such classes are omitted if the original classes cannot be found. If
!      * multiple classes are specified using {@link #className()} and {@link #optional()} is false,
!      * then at least one of the classes is required to be reachable.
       */
      boolean optional() default false;
  }