8078268: javax.swing.text.html.parser.Parser parseScript incorrectly optimized

Reviewed-by: alexp, aivanov

src/share/classes/javax/swing/text/html/parser/Parser.java

@@ -1993,17 +1993,37 @@ class Parser implements DTDConstants {
                 i++;
             }
             if (i == SCRIPT_END_TAG.length) {
-
-                /*  '</script>' tag detected */
-                /* Here, ch == the first character after </script> */
                 return;
-            } else {
+            }
+
+            if (!insideComment && i == 1 && charsToAdd[0] == START_COMMENT.charAt(0)) {
+                // it isn't end script tag, but may be it's start comment tag?
+                while (i < START_COMMENT.length()
+                        && START_COMMENT.charAt(i) == ch) {
+                    charsToAdd[i] = (char) ch;
+                    ch = readCh();
+                    i++;
+                }
+                if (i == START_COMMENT.length()) {
+                    insideComment = true;
+                }
+            }
+            if (insideComment) {
+                while (i < END_COMMENT.length()
+                        && END_COMMENT.charAt(i) == ch) {
+                    charsToAdd[i] = (char) ch;
+                    ch = readCh();
+                    i++;
+                }
+                if (i == END_COMMENT.length()) {
+                    insideComment = false;
+                }
+            }
 
             /* To account for extra read()'s that happened */
             for (int j = 0; j < i; j++) {
                 addString(charsToAdd[j]);
             }
-
             switch (ch) {
             case -1:
                 error("eof.script");
@@ -2026,17 +2046,9 @@ class Parser implements DTDConstants {
                 break;
             default:
                 addString(ch);
-                    String str = new String(getChars(0, strpos));
-                    if (!insideComment && str.endsWith(START_COMMENT)) {
-                        insideComment = true;
-                    }
-                    if (insideComment && str.endsWith(END_COMMENT)) {
-                        insideComment = false;
-                    }
                 ch = readCh();
                 break;
             } // switch
-            }
         } // while
     }