src/jdk.compiler/share/classes/com/sun/tools/javac/main/Option.java

*** 810,10 ***
--- 810,11 ---
              }
          }
      },
  
      MULTIRELEASE("--multi-release", "opt.arg.multi-release", "opt.multi-release", HIDDEN, FILEMANAGER),
+     PREVIEWMODE("--preview-mode", "opt.arg.preview-mode", "opt.preview-mode", HIDDEN, FILEMANAGER),
  
      INHERIT_RUNTIME_ENVIRONMENT("--inherit-runtime-environment", "opt.inherit_runtime_environment",
              HIDDEN, BASIC) {
          @Override
          public void process(OptionHelper helper, String option) throws InvalidValueException {