Issue #4564: fixed exception on JavadocStyle's skip html comment

src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/TagParser.java

@@ -212,8 +212,8 @@ private static boolean isCommentTag(String[] text, Point pos) {
     private static Point skipHtmlComment(String[] text, Point fromPoint) {
         Point toPoint = fromPoint;
         toPoint = findChar(text, '>', toPoint);
-        while (!text[toPoint.getLineNo()]
-               .substring(0, toPoint.getColumnNo() + 1).endsWith("-->")) {
+        while (toPoint.getLineNo() < text.length && !text[toPoint.getLineNo()]
+                .substring(0, toPoint.getColumnNo() + 1).endsWith("-->")) {
             toPoint = findChar(text, '>', getNextCharPos(text, toPoint));
         }
         return toPoint;

src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocStyleCheckTest.java

@@ -423,4 +423,12 @@ public void testHtmlTagToString() {
                 + "closedTag=true, incompleteTag=false]", tag.toString());
     }
 
+    @Test
+    public void testNeverEndingXmlCommentInsideJavadoc() throws Exception {
+        final DefaultConfiguration checkConfig = createModuleConfig(JavadocStyleCheck.class);
+        final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
+
+        verify(checkConfig, getPath("InputJavadocStyleNeverEndingXmlComment.java"), expected);
+    }
+
 }

src/test/resources/com/puppycrawl/tools/checkstyle/checks/javadoc/javadocstyle/InputJavadocStyleNeverEndingXmlComment.java

@@ -0,0 +1,6 @@
+package com.puppycrawl.tools.checkstyle.checks.javadoc.javadocstyle;
+
+public class InputJavadocStyleNeverEndingXmlComment {
+    /** DTD: <!--. */
+    public int i;
+}