8324126: Error message for mistyping -XX:+Unlock...Options is not helpful

Reviewed-by: dholmes, stuefe

Author: Sonia Zaldana Calles

src/hotspot/share/runtime/arguments.cpp

@@ -1119,18 +1119,7 @@ bool Arguments::process_argument(const char* arg,
   if (found_flag != nullptr) {
     char locked_message_buf[BUFLEN];
     JVMFlag::MsgType msg_type = found_flag->get_locked_message(locked_message_buf, BUFLEN);
-    if (strlen(locked_message_buf) == 0) {
-      if (found_flag->is_bool() && !has_plus_minus) {
-        jio_fprintf(defaultStream::error_stream(),
-          "Missing +/- setting for VM option '%s'\n", argname);
-      } else if (!found_flag->is_bool() && has_plus_minus) {
-        jio_fprintf(defaultStream::error_stream(),
-          "Unexpected +/- setting in VM option '%s'\n", argname);
-      } else {
-        jio_fprintf(defaultStream::error_stream(),
-          "Improperly specified VM option '%s'\n", argname);
-      }
-    } else {
+    if (strlen(locked_message_buf) != 0) {
 #ifdef PRODUCT
       bool mismatched = ((msg_type == JVMFlag::NOTPRODUCT_FLAG_BUT_PRODUCT_BUILD) ||
                          (msg_type == JVMFlag::DEVELOPER_FLAG_BUT_PRODUCT_BUILD));
@@ -1140,6 +1129,16 @@ bool Arguments::process_argument(const char* arg,
 #endif
       jio_fprintf(defaultStream::error_stream(), "%s", locked_message_buf);
     }
+    if (found_flag->is_bool() && !has_plus_minus) {
+      jio_fprintf(defaultStream::error_stream(),
+        "Missing +/- setting for VM option '%s'\n", argname);
+    } else if (!found_flag->is_bool() && has_plus_minus) {
+      jio_fprintf(defaultStream::error_stream(),
+        "Unexpected +/- setting in VM option '%s'\n", argname);
+    } else {
+      jio_fprintf(defaultStream::error_stream(),
+        "Improperly specified VM option '%s'\n", argname);
+    }
   } else {
     if (ignore_unrecognized) {
       return true;

test/hotspot/jtreg/runtime/CommandLine/TestVMOptions.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -59,5 +59,11 @@ public static void main(String[] args) throws Exception {
     output = new OutputAnalyzer(pb.start());
     output.shouldNotHaveExitValue(0);
     output.shouldContain("VM option '-IgnoreUnrecognizedVMOptions'");
+
+    pb = ProcessTools.createLimitedTestJavaProcessBuilder(
+            "-XX:UnlockExperimentalVMOptions");
+    output = new OutputAnalyzer(pb.start());
+    output.stderrShouldContain("VM option 'UnlockExperimentalVMOptions' is experimental and must be enabled via -XX:+UnlockExperimentalVMOptions.");
+    output.stderrShouldContain("Missing +/- setting for VM option 'UnlockExperimentalVMOptions'");
   }
 }