diff --git a/ale_linters/java/checkstyle.vim b/ale_linters/java/checkstyle.vim
index f00734e0..1ccbc505 100644
--- a/ale_linters/java/checkstyle.vim
+++ b/ale_linters/java/checkstyle.vim
@@ -14,6 +14,7 @@ function! ale_linters#java#checkstyle#Handle(buffer, lines) abort
     for l:match in ale#util#GetMatches(a:lines, l:pattern)
         call add(l:output, {
         \   'type': l:match[1] is? 'WARN' ? 'W' : 'E',
+        \   'sub_type': 'style',
         \   'lnum': l:match[2] + 0,
         \   'col': l:match[3] + 0,
         \   'text': l:match[4],
@@ -31,6 +32,7 @@ function! ale_linters#java#checkstyle#Handle(buffer, lines) abort
     for l:match in ale#util#GetMatches(a:lines, l:pattern)
         call add(l:output, {
         \   'type': l:match[3] is? 'warning' ? 'W' : 'E',
+        \   'sub_type': 'style',
         \   'lnum': l:match[2] + 0,
         \   'text': l:match[4],
         \})
diff --git a/test/handler/test_checkstyle_handler.vader b/test/handler/test_checkstyle_handler.vader
index c60bbc82..ea90db3f 100644
--- a/test/handler/test_checkstyle_handler.vader
+++ b/test/handler/test_checkstyle_handler.vader
@@ -13,6 +13,7 @@ Execute(The checkstyle handler should parse lines correctly):
   \     'text': '''method def rcurly'' has incorrect indentation level 4, expected level should be 2.',
   \     'code': 'Indentation',
   \     'type': 'W',
+  \     'sub_type': 'style',
   \   },
   \   {
   \     'lnum': 63,
@@ -20,6 +21,7 @@ Execute(The checkstyle handler should parse lines correctly):
   \     'text': 'Missing a Javadoc comment.',
   \     'code': 'JavadocMethod',
   \     'type': 'W',
+  \     'sub_type': 'style',
   \   },
   \   {
   \     'lnum': 11,
@@ -27,6 +29,7 @@ Execute(The checkstyle handler should parse lines correctly):
   \     'text': 'WhitespaceAround: ''if'' is not followed by whitespace.',
   \     'code': 'WhitespaceAround',
   \     'type': 'W',
+  \     'sub_type': 'style',
   \   },
   \ ],
   \ ale_linters#java#checkstyle#Handle(666, [
@@ -42,6 +45,7 @@ Execute(The checkstyle handler should parse lines from older checkstyle versions
   \     'lnum': 289,
   \     'text': '''method def modifier'' have incorrect indentation level 4, expected level should be 2.',
   \     'type': 'W',
+  \     'sub_type': 'style',
   \   },
   \ ],
   \ ale_linters#java#checkstyle#Handle(666, [