Fixing thread safety of string matching

Based on 361656d

otp-core/src/main/java/org/opentripplanner/util/LocalizedString.java

@@ -28,8 +28,7 @@ the License, or (at your option) any later version.
  * @author mabu
  */
 public class LocalizedString implements I18NString, Serializable {
-    private static final Pattern pattern = Pattern.compile("\\{(.*?)\\}");
-    private static final Matcher matcher = pattern.matcher("");
+    private static final Pattern patternMatcher = Pattern.compile("\\{(.*?)\\}");
 
     /**
      * Map which key has which tagName. Used only when building graph.
@@ -100,7 +99,8 @@ private String getTagNames() {
             return key_params.get(key);
         }
         String english_trans = ResourceBundleSingleton.INSTANCE.localize(this.key, Locale.ENGLISH);
-        matcher.reset(english_trans);
+
+        Matcher matcher = patternMatcher.matcher(english_trans);
         int lastEnd = 0;
         while (matcher.find()) {
 
@@ -127,7 +127,7 @@ public String toString(Locale locale) {
         //in string formatting with values from way tags values
         String translation = ResourceBundleSingleton.INSTANCE.localize(this.key, locale);
         if (this.params != null) {
-            translation = pattern.matcher(translation).replaceFirst("%s");
+            translation = patternMatcher.matcher(translation).replaceFirst("%s");
             return String.format(translation, (Object[]) params);
         } else {
             return translation;