8343804: Show the default time zone with -XshowSettings option

Reviewed-by: phh
Backport-of: 0329855831102a48abf14b5befc933f84dfd3460

Author: GoeLin

src/java.base/share/classes/sun/launcher/LauncherHelper.java

@@ -71,6 +71,7 @@
 import java.util.Properties;
 import java.util.ResourceBundle;
 import java.util.Set;
+import java.util.TimeZone;
 import java.util.TreeSet;
 import java.util.jar.Attributes;
 import java.util.jar.JarFile;
@@ -295,6 +296,8 @@ private static void printLocale(boolean summaryMode) {
                 Locale.getDefault(Category.DISPLAY).getDisplayName());
         ostream.println(INDENT + "default format locale = " +
                 Locale.getDefault(Category.FORMAT).getDisplayName());
+        ostream.println(INDENT + "default timezone = " +
+                TimeZone.getDefault().getID());
         ostream.println(INDENT + "tzdata version = " +
                 ZoneInfoFile.getVersion());
         if (!summaryMode) {

test/jdk/tools/launcher/Settings.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 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
@@ -79,6 +79,7 @@ static void checkNotContains(TestResult tr, String str) {
     private static final String BAD_SEC_OPTION_MSG = "Unrecognized security subcommand";
     private static final String SYSTEM_SETTINGS = "Operating System Metrics:";
     private static final String STACKSIZE_SETTINGS = "Stack Size:";
+    private static final String TIMEZONE_SETTINGS = "default timezone";
     private static final String TZDATA_SETTINGS = "tzdata version";
 
     static void containsAllOptions(TestResult tr) {
@@ -92,6 +93,7 @@ static void containsAllOptions(TestResult tr) {
         checkContains(tr, SEC_SUMMARY_PROPS_SETTINGS);
         checkContains(tr, SEC_PROVIDER_SETTINGS);
         checkContains(tr, SEC_TLS_SETTINGS);
+        checkContains(tr, TIMEZONE_SETTINGS);
         checkContains(tr, TZDATA_SETTINGS);
         if (System.getProperty("os.name").contains("Linux")) {
             checkContains(tr, SYSTEM_SETTINGS);
@@ -160,6 +162,7 @@ static void runTestOptionLocale() throws IOException {
         checkContains(tr, LOCALE_SETTINGS);
         checkContains(tr, AVAILABLE_LOCALES);
         checkNotContains(tr, LOCALE_SUMMARY_SETTINGS);
+        checkContains(tr, TIMEZONE_SETTINGS);
         checkContains(tr, TZDATA_SETTINGS);
     }