runtime(java): Recognise the {@snippet} documentation tag (#14271)

Remember that ‘code fragments are typically Java source
code, but they may also be fragments of properties files,
source code in other languages, or plain text.’  Therefore,
with these changes, markup tags are highlighted in the Java
source files (as external snippets) and in the {@snippet}
tags.

Also:

- Improve matching of the multi-line {@code} documentation
  tag with any contained balanced braces.
- Recognise the {@literal} documentation tag.
- Highlight stray blanks in comments.

Related to an enhancement proposal for PCRE-like callouts
discussed at https://github.com/vim/vim/issues/11217.

References:
https://openjdk.org/jeps/413
https://docs.oracle.com/en/java/javase/21/docs/specs/javadoc/doc-comment-spec.html

Signed-off-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/runtime/syntax/java.vim b/runtime/syntax/java.vim
index c059de603c773054c86dfafb04727cd22adf496a..fe0cabf58eae8b4323714b0542595b5cf98f8849 100644 (file)
--- a/runtime/syntax/java.vim
+++ b/runtime/syntax/java.vim
@@ -2,7 +2,7 @@
 " Language:    Java
 " Maintainer:  Claudio Fleiner <claudio@fleiner.com>
 " URL:          https://github.com/fleiner/vim/blob/master/runtime/syntax/java.vim
-" Last Change: 2024 Mar 06
+" Last Change: 2024 Mar 22
 
 " Please check :help java.vim for comments on some of the options available.
 
@@ -191,10 +191,14 @@ if exists("java_comment_strings")
   syn cluster javaCommentSpecial2 add=javaComment2String,javaCommentCharacter,javaNumber,javaStrTempl
 endif
 
-syn region  javaComment                 start="/\*"  end="\*/" contains=@javaCommentSpecial,javaTodo,@Spell
+syn region  javaComment                start="/\*" end="\*/" contains=@javaCommentSpecial,javaTodo,javaSpaceError,@Spell
 syn match   javaCommentStar     contained "^\s*\*[^/]"me=e-1
 syn match   javaCommentStar     contained "^\s*\*$"
-syn match   javaLineComment     "//.*" contains=@javaCommentSpecial2,javaTodo,@Spell
+syn match   javaLineComment    "//.*" contains=@javaCommentSpecial2,javaTodo,javaCommentMarkupTag,javaSpaceError,@Spell
+syn match   javaCommentMarkupTag contained "@\%(end\|highlight\|link\|replace\|start\)\>" nextgroup=javaCommentMarkupTagAttr skipwhite
+syn match   javaCommentMarkupTagAttr contained "\<region\>" nextgroup=javaCommentMarkupTagAttr skipwhite
+syn region  javaCommentMarkupTagAttr contained transparent matchgroup=htmlArg start=/\<\%(re\%(gex\|gion\|placement\)\|substring\|t\%(arget\|ype\)\)\%(\s*=\)\@=/ matchgroup=htmlString end=/\%(=\s*\)\@<=\%("[^"]\+"\|'[^']\+'\|\%([.-]\|\k\)\+\)/ nextgroup=javaCommentMarkupTagAttr skipwhite oneline
+hi def link javaCommentMarkupTagAttr htmlArg
 hi def link javaCommentString javaString
 hi def link javaComment2String javaString
 hi def link javaCommentCharacter javaCharacter
@@ -211,15 +215,19 @@ if !exists("java_ignore_javadoc") && main_syntax != 'jsp'
   " here.
   syntax spell default
 
-  syn region  javaDocComment   start="/\*\*"  end="\*/" keepend contains=javaCommentTitle,@javaHtml,javaDocTags,javaDocSeeTag,javaTodo,@Spell
-  syn region  javaCommentTitle contained matchgroup=javaDocComment start="/\*\*"   matchgroup=javaCommentTitle keepend end="\.$" end="\.[ \t\r<&]"me=e-1 end="[^{]@"me=s-2,he=s-1 end="\*/"me=s-1,he=s-1 contains=@javaHtml,javaCommentStar,javaTodo,@Spell,javaDocTags,javaDocSeeTag
-
-  syn region javaDocTags        contained start="{@\(code\|link\|linkplain\|inherit[Dd]oc\|doc[rR]oot\|value\)" end="}"
+  syn region javaDocComment    start="/\*\*" end="\*/" keepend contains=javaCommentTitle,@javaHtml,javaDocTags,javaDocSeeTag,javaDocCodeTag,javaDocSnippetTag,javaTodo,javaSpaceError,@Spell
+  syn region javaCommentTitle  contained matchgroup=javaDocComment start="/\*\*" matchgroup=javaCommentTitle keepend end="\.$" end="\.[ \t\r<&]"me=e-1 end="[^{]@"me=s-2,he=s-1 end="\*/"me=s-1,he=s-1 contains=@javaHtml,javaCommentStar,javaTodo,javaSpaceError,@Spell,javaDocTags,javaDocSeeTag,javaDocCodeTag,javaDocSnippetTag
+  syn region javaDocTags       contained start="{@\%(li\%(teral\|nk\%(plain\)\=\)\|inherit[Dd]oc\|doc[rR]oot\|value\)\>" end="}"
   syn match  javaDocTags        contained "@\(param\|exception\|throws\|since\)\s\+\S\+" contains=javaDocParam
   syn match  javaDocParam       contained "\s\S\+"
   syn match  javaDocTags        contained "@\(version\|author\|return\|deprecated\|serial\|serialField\|serialData\)\>"
   syn region javaDocSeeTag      contained matchgroup=javaDocTags start="@see\s\+" matchgroup=NONE end="\_."re=e-1 contains=javaDocSeeTagParam
   syn match  javaDocSeeTagParam  contained @"\_[^"]\+"\|<a\s\+\_.\{-}</a>\|\(\k\|\.\)*\(#\k\+\((\_[^)]\+)\)\=\)\=@ extend
+  syn region javaCodeSkipBlock contained transparent start="{\%(@code\>\)\@!" end="}" contains=javaCodeSkipBlock,javaDocCodeTag
+  syn region javaDocCodeTag    contained start="{@code\>" end="}" contains=javaDocCodeTag,javaCodeSkipBlock
+  syn region javaDocSnippetTagAttr contained transparent matchgroup=htmlArg start=/\<\%(class\|file\|id\|lang\|region\)\%(\s*=\)\@=/ matchgroup=htmlString end=/:$/ end=/\%(=\s*\)\@<=\%("[^"]\+"\|'[^']\+'\|\%([.-]\|\k\)\+\)/ nextgroup=javaDocSnippetTagAttr skipwhite skipnl
+  syn region javaSnippetSkipBlock contained transparent start="{\%(@snippet\>\)\@!" end="}" contains=javaSnippetSkipBlock,javaDocSnippetTag,javaCommentMarkupTag
+  syn region javaDocSnippetTag contained start="{@snippet\>" end="}" contains=javaDocSnippetTag,javaSnippetSkipBlock,javaDocSnippetTagAttr,javaCommentMarkupTag
   syntax case match
 endif
 
@@ -404,6 +412,8 @@ hi def link javaAnnotation          PreProc
 
 hi def link javaCommentTitle           SpecialComment
 hi def link javaDocTags                Special
+hi def link javaDocCodeTag             Special
+hi def link javaDocSnippetTag          Special
 hi def link javaDocParam               Function
 hi def link javaDocSeeTagParam         Function
 hi def link javaCommentStar            javaComment
@@ -413,6 +423,8 @@ hi def link javaExternal            Include
 
 hi def link htmlComment                Special
 hi def link htmlCommentPart            Special
+hi def link htmlArg                    Type
+hi def link htmlString                 String
 hi def link javaSpaceError             Error
 
 if s:isModuleInfoDeclarationCurrentBuffer()

diff --git a/runtime/syntax/testdir/dumps/java_comments_00.dump b/runtime/syntax/testdir/dumps/java_comments_00.dump
new file mode 100644 (file)
index 0000000..bc1f359
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/java_comments_00.dump
@@ -0,0 +1,20 @@
+>/+0#0000e05#ffffff0@1| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |u|n|l|e|t|!| |g+0&#5fd7ff255|:+0&#ffffff0|j|a|v|a|_|i|g|n|o|r|e|_|j+0&#ffd7d7255|a|v|a|d|o|c| +0&#ffffff0|g|:|j|a|v|a|_|n|o|_|t|r|a|i|l|_|s|p|a|c|e|_|e|r@1|o|r| +0#ffffff16#ff404010
+|/+0#0000e05#ffffff0@1| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |u|n|l|e|t|!| |g+0&#5fd7ff255|:+0&#ffffff0|j|a|v|a|_|n|o|_|t|a|b|_|s|p|a|c|e|_|e|r@1|o|r| +0#ffffff16#ff404010@1| +0#0000000#ffffff0@22
+|/+0#0000e05&@1| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |l|e|t| |[|g|:|j|a|v|a|_|s|p|a|c|e|_|e|r@1|o|r|s|,|g|:|j|a|v|a|_|c|o|m@1|e|n|t|_|s|t|r|i|n|g|s|]| |=| |[|1+0#e000002&|,+0#0000e05&|1+0#e000002&|]+0#0000e05&| +0#0000000&
+|/+0#0000e05&@1| +0#ffffff16#ff404010| +0#0000e05#ffffff0|V|I|M|_|T|E|S|T|_|S|E|T|U|P| |s+0&#ffd7d7255|e|t|l|o|c|a|l| +0&#ffffff0|s|p|e|l@1| +0#0000000&@41
+|c+0#00e0003&|l|a|s@1| +0#0000000&|C|o|m@1|e|n|t|s|T|e|s|t|s| @55
+|{| @2|/+0#0000e05&|*| +0#ffffff16#ff404010| +0#0000e05#ffffff0|T|R|A|I|L|I|N|G| |B|L|A|N|K|S| |A|N|D| |M+0&#ffd7d7255|E|S@1|P|I|L@1|I|N|G|S| +0&#ffffff0|A|R|E| |S|I|G|N|I|F|I|C|A|N|T|!| |*|/| +0#ffffff16#ff404010@3| +0#0000000#ffffff0@10
+@4|/+0#0000e05&|*@1| +0#ffffff16#ff404010| +0#0000000#ffffff0@66
+| +0#0000e05&@4|*| +0#e000e06&|T|h|e| |m|e|t|h|o|d| |{|@|c|o|d|e| |m|a|i|n|}| |m|u|s|t| |b|e| |d|e|c|l|a|r|e|d| |{|@|c|o|d|e| |p|u|b|l|i|c|}|,| |{|@|c|o|d|e| +0#0000000&@4
+| +0#e000e06&@4|*| |s|t|a|t|i|c|}|,| |a|n|d| |{|@|c|o|d|e| |v|o|i|d|}|.| +0#0000e05&@1|I|t| |m|u|s|t| |s|p|e|c|i|f|y| |a| |f|o|r|m|a|l| |p|a|r|a|m|e|t|e|r| +0#0000000&@5
+| +0#0000e05&@4|*| |w|h|o|s|e| |d|e|c|l|a|r|e|d| |t|y|p|e| |i|s| |a|r@1|a|y| |o|f| |{+0#e000e06&|@|l|i|n|k| |S|t|r|i|n|g|}|.+0#0000e05&| @1|T|h|e|r|e|f|o|r|e|,| +0#0000000&@8
+| +0#0000e05&@4|*| |e|i|t|h|e|r| |o|f| |t|h|e| |f|o|l@1|o|w|i|n|g| |d|e|c|l|a|r|a|t|i|o|n|s| |i|s| |a|c@1|e|p|t|a|b|l|e|:| +0#0000000&@16
+| +0#0000e05&@4|*| +0#ffffff16#ff404010| +0#0000e05#ffffff0|{+0#e000e06&|@|s|n|i|p@1|e|t| |l+0#00e0003&|a|n|g|=+0#e000e06&|"+0#e000002&|j|a|v|a|"|:+0#e000e06&| +0#0000000&@44
+| +0#e000e06&@4|*| |/@1| |@+0#0000000&|h|i|g|h|l|i|g|h|t| +0#e000e06&|s+0#00e0003&|u|b|s|t|r|i|n|g|=+0#e000e06&|"+0#e000002&|m|a|i|n|"| +0#e000e06&|t+0#00e0003&|y|p|e|=+0#e000e06&|"+0#e000002&|i|t|a|l|i|c|"|:+0#e000e06&| +0#0000000&@22
+| +0#e000e06&@4|*| |p|u|b|l|i|c| |s|t|a|t|i|c| |v|o|i|d| |m|a|i|n|(|S|t|r|i|n|g|[|]| |a|r|g|s|)| |{| |}| +0#0000000&@25
+| +0#e000e06&@4|*| |}|<+0#00e0e07&|b+0#af5f00255&|r| +0#00e0e07&|/|>|<|p+0#af5f00255&|r|e| +0#00e0e07&|c+0#00e0003&|l|a|s@1|=+0#00e0e07&|"+0#e000002&|s|n|i|p@1|e|t|"|>+0#00e0e07&| +0#0000000&@39
+| +0#0000e05&@4|*|{+0#e000e06&|@|c|o|d|e| |p|u|b|l|i|c| |s|t|a|t|i|c| |v|o|i|d| |m|a|i|n|(|S|t|r|i|n|g|.@2| |a|r|g|s|)| |{| |}@1|<+0#00e0e07&|/|p+0#af5f00255&|r|e|>+0#00e0e07&| +0#0000000&@11
+| +0#0000e05&@4|*| +0#0000000&@68
+| +0#0000e05&@4|*| |@+0#e000e06&|p|a|r|a|m| +0#00e0e07&|a|r|g|s| +0#0000e05&|o|p|t|i|o|n|a|l| |c+0&#ffd7d7255|o|m@1|a|n|d|e|-+0&#ffffff0|l|i|n|e| |a|r|g|u|m|e|n|t|s| +0#ffffff16#ff404010| +0#0000000#ffffff0@22
+| +0#0000e05&@4|*| |@|j+0&#ffd7d7255|l|s| +0&#ffffff0|1|2|.|1|.|4| |I|n|v|o|k|e| |{+0#e000e06&|@|c|o|d|e| |T|e|s|t|.|m|a|i|n|}| +0#0000000&@31
+@57|1|,|1| @10|T|o|p| 

diff --git a/runtime/syntax/testdir/dumps/java_comments_01.dump b/runtime/syntax/testdir/dumps/java_comments_01.dump
new file mode 100644 (file)
index 0000000..9f92f83
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/java_comments_01.dump
@@ -0,0 +1,20 @@
+| +0#e000e06#ffffff0@4|*| |p|u|b|l|i|c| |s|t|a|t|i|c| |v|o|i|d| |m|a|i|n|(|S|t|r|i|n|g|[|]| |a|r|g|s|)| |{| |}| +0#0000000&@25
+| +0#e000e06&@4|*| |}|<+0#00e0e07&|b+0#af5f00255&|r| +0#00e0e07&|/|>|<|p+0#af5f00255&|r|e| +0#00e0e07&|c+0#00e0003&|l|a|s@1|=+0#00e0e07&|"+0#e000002&|s|n|i|p@1|e|t|"|>+0#00e0e07&| +0#0000000&@39
+| +0#0000e05&@4|*|{+0#e000e06&|@|c|o|d|e| |p|u|b|l|i|c| |s|t|a|t|i|c| |v|o|i|d| |m|a|i|n|(|S|t|r|i|n|g|.@2| |a|r|g|s|)| |{| |}@1|<+0#00e0e07&|/|p+0#af5f00255&|r|e|>+0#00e0e07&| +0#0000000&@11
+| +0#0000e05&@4|*| +0#0000000&@68
+| +0#0000e05&@4|*| |@+0#e000e06&|p|a|r|a|m| +0#00e0e07&|a|r|g|s| +0#0000e05&|o|p|t|i|o|n|a|l| |c+0&#ffd7d7255|o|m@1|a|n|d|e|-+0&#ffffff0|l|i|n|e| |a|r|g|u|m|e|n|t|s| +0#ffffff16#ff404010| +0#0000000#ffffff0@22
+| +0#0000e05&@4>*| |@|j+0&#ffd7d7255|l|s| +0&#ffffff0|1|2|.|1|.|4| |I|n|v|o|k|e| |{+0#e000e06&|@|c|o|d|e| |T|e|s|t|.|m|a|i|n|}| +0#0000000&@31
+| +0#0000e05&@4|*|/| +0#0000000&@67
+@4|/+0#0000e05&@1| |@+0#0000000&|s|t|a|r|t| +0#0000e05&|r+0#00e0003&|e|g|i|o|n| +0#0000e05&|=| |m+0#e000002&|a|i|n| +0#0000000&@47
+@4|/+0#0000e05&@1| |@+0#0000000&|l|i|n|k| +0#0000e05&|s+0#00e0003&|u|b|s|t|r|i|n|g| +0#0000e05&|=| |'+0#e000002&|S|t|r|i|n|g|'| +0#0000e05&|t+0#00e0003&|a|r|g|e|t| +0#0000e05&|=| |'+0#e000002&|j|a|v|a|.|l|a|n|g|.|S|t|r|i|n|g|'| +0#0000e05&|:| +0#0000000&@11
+@4|p+0#00e0003&|u|b|l|i|c| +0#0000000&|s+0#00e0003&|t|a|t|i|c| +0#0000000&|v+0#00e0003&|o|i|d| +0#0000000&|m|a|i|n|(|S|t|r|i|n|g|[|]| |a|r|g|s|)| |{| |}| @28
+@4|/+0#0000e05&@1| |@+0#0000000&|e|n|d| @63
+|}| @73
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|9|,|3|-|6| @7|B|o|t| 

diff --git a/runtime/syntax/testdir/dumps/java_comments_99.dump b/runtime/syntax/testdir/dumps/java_comments_99.dump
new file mode 100644 (file)
index 0000000..024dc48
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/java_comments_99.dump
@@ -0,0 +1,20 @@
+| +0&#ffffff0@3|/+0#0000e05&|*@1| +0#ffffff16#ff404010| +0#0000000#ffffff0@66
+| +0#0000e05&@4|*| +0#e000e06&|T|h|e| |m|e|t|h|o|d| |{|@|c|o|d|e| |m|a|i|n|}| |m|u|s|t| |b|e| |d|e|c|l|a|r|e|d| |{|@|c|o|d|e| |p|u|b|l|i|c|}|,| |{|@|c|o|d|e| +0#0000000&@4
+| +0#e000e06&@4|*| |s|t|a|t|i|c|}|,| |a|n|d| |{|@|c|o|d|e| |v|o|i|d|}|.| +0#0000e05&@1|I|t| |m|u|s|t| |s|p|e|c|i|f|y| |a| |f|o|r|m|a|l| |p|a|r|a|m|e|t|e|r| +0#0000000&@5
+| +0#0000e05&@4|*| |w|h|o|s|e| |d|e|c|l|a|r|e|d| |t|y|p|e| |i|s| |a|r@1|a|y| |o|f| |{+0#e000e06&|@|l|i|n|k| |S|t|r|i|n|g|}|.+0#0000e05&| @1|T|h|e|r|e|f|o|r|e|,| +0#0000000&@8
+| +0#0000e05&@4|*| |e|i|t|h|e|r| |o|f| |t|h|e| |f|o|l@1|o|w|i|n|g| |d|e|c|l|a|r|a|t|i|o|n|s| |i|s| |a|c@1|e|p|t|a|b|l|e|:| +0#0000000&@16
+| +0#0000e05&@4|*| +0#ffffff16#ff404010| +0#0000e05#ffffff0|{+0#e000e06&|@|s|n|i|p@1|e|t| |l+0#00e0003&|a|n|g|=+0#e000e06&|"+0#e000002&|j|a|v|a|"|:+0#e000e06&| +0#0000000&@44
+| +0#e000e06&@4|*| |/@1| |@+0#0000000&|h|i|g|h|l|i|g|h|t| +0#e000e06&|s+0#00e0003&|u|b|s|t|r|i|n|g|=+0#e000e06&|"+0#e000002&|m|a|i|n|"| +0#e000e06&|t+0#00e0003&|y|p|e|=+0#e000e06&|"+0#e000002&|i|t|a|l|i|c|"|:+0#e000e06&| +0#0000000&@22
+| +0#e000e06&@4|*| |p|u|b|l|i|c| |s|t|a|t|i|c| |v|o|i|d| |m|a|i|n|(|S|t|r|i|n|g|[|]| |a|r|g|s|)| |{| |}| +0#0000000&@25
+| +0#e000e06&@4|*| |}|<+0#00e0e07&|b+0#af5f00255&|r| +0#00e0e07&|/|>|<|p+0#af5f00255&|r|e| +0#00e0e07&|c+0#00e0003&|l|a|s@1|=+0#00e0e07&|"+0#e000002&|s|n|i|p@1|e|t|"|>+0#00e0e07&| +0#0000000&@39
+| +0#0000e05&@4|*|{+0#e000e06&|@|c|o|d|e| |p|u|b|l|i|c| |s|t|a|t|i|c| |v|o|i|d| |m|a|i|n|(|S|t|r|i|n|g|.@2| |a|r|g|s|)| |{| |}@1|<+0#00e0e07&|/|p+0#af5f00255&|r|e|>+0#00e0e07&| +0#0000000&@11
+| +0#0000e05&@4|*| +0#0000000&@68
+| +0#0000e05&@4|*| |@+0#e000e06&|p|a|r|a|m| +0#00e0e07&|a|r|g|s| +0#0000e05&|o|p|t|i|o|n|a|l| |c+0&#ffd7d7255|o|m@1|a|n|d|e|-+0&#ffffff0|l|i|n|e| |a|r|g|u|m|e|n|t|s| +0#ffffff16#ff404010| +0#0000000#ffffff0@22
+| +0#0000e05&@4|*| |@|j+0&#ffd7d7255|l|s| +0&#ffffff0|1|2|.|1|.|4| |I|n|v|o|k|e| |{+0#e000e06&|@|c|o|d|e| |T|e|s|t|.|m|a|i|n|}| +0#0000000&@31
+| +0#0000e05&@4|*|/| +0#0000000&@67
+@4|/+0#0000e05&@1| |@+0#0000000&|s|t|a|r|t| +0#0000e05&|r+0#00e0003&|e|g|i|o|n| +0#0000e05&|=| |m+0#e000002&|a|i|n| +0#0000000&@47
+@4|/+0#0000e05&@1| |@+0#0000000&|l|i|n|k| +0#0000e05&|s+0#00e0003&|u|b|s|t|r|i|n|g| +0#0000e05&|=| |'+0#e000002&|S|t|r|i|n|g|'| +0#0000e05&|t+0#00e0003&|a|r|g|e|t| +0#0000e05&|=| |'+0#e000002&|j|a|v|a|.|l|a|n|g|.|S|t|r|i|n|g|'| +0#0000e05&|:| +0#0000000&@11
+@4|p+0#00e0003&|u|b|l|i|c| +0#0000000&|s+0#00e0003&|t|a|t|i|c| +0#0000000&|v+0#00e0003&|o|i|d| +0#0000000&|m|a|i|n|(|S|t|r|i|n|g|[|]| |a|r|g|s|)| |{| |}| @28
+@4|/+0#0000e05&@1| |@+0#0000000&|e|n|d| @63
+>}| @73
+@57|2|5|,|1| @9|B|o|t| 

diff --git a/runtime/syntax/testdir/input/java_comments.java b/runtime/syntax/testdir/input/java_comments.java
new file mode 100644 (file)
index 0000000..be347d7
--- /dev/null
+++ b/runtime/syntax/testdir/input/java_comments.java
@@ -0,0 +1,25 @@
+// VIM_TEST_SETUP unlet! g:java_ignore_javadoc g:java_no_trail_space_error 
+// VIM_TEST_SETUP unlet! g:java_no_tab_space_error     
+// VIM_TEST_SETUP let [g:java_space_errors,g:java_comment_strings] = [1,1]
+//     VIM_TEST_SETUP setlocal spell
+class CommentsTests
+{      /*      TRAILING BLANKS AND MESSPILLINGS ARE SIGNIFICANT! */    
+       /**     
+        * The method {@code main} must be declared {@code public}, {@code
+        * static}, and {@code void}.  It must specify a formal parameter
+        * whose declared type is array of {@link String}.  Therefore,
+        * either of the following declarations is acceptable:
+        *      {@snippet lang="java":
+        * // @highlight substring="main" type="italic":
+        * public static void main(String[] args) { }
+        * }<br /><pre class="snippet">
+        *{@code public static void main(String... args) { }}</pre>
+        *
+        * @param args optional commande-line arguments 
+        * @jls 12.1.4 Invoke {@code Test.main}
+        */
+       // @start region = main
+       // @link substring = 'String' target = 'java.lang.String' :
+       public static void main(String[] args) { }
+       // @end
+}