src/java.base/share/classes/sun/net/www/MessageHeader.java

*** 242,252 ****
      }
  
      public synchronized Map<String, List<String>> filterAndAddHeaders(
              String[] excludeList, Map<String, List<String>>  include) {
          boolean skipIt = false;
!         Map<String, List<String>> m = new HashMap<String, List<String>>();
          for (int i = nkeys; --i >= 0;) {
              if (excludeList != null) {
                  // check if the key is in the excludeList.
                  // if so, don't include it in the Map.
                  for (int j = 0; j < excludeList.length; j++) {
--- 242,252 ----
      }
  
      public synchronized Map<String, List<String>> filterAndAddHeaders(
              String[] excludeList, Map<String, List<String>>  include) {
          boolean skipIt = false;
!         Map<String, List<String>> m = new HashMap<>();
          for (int i = nkeys; --i >= 0;) {
              if (excludeList != null) {
                  // check if the key is in the excludeList.
                  // if so, don't include it in the Map.
                  for (int j = 0; j < excludeList.length; j++) {
*** 258,268 ****
                  }
              }
              if (!skipIt) {
                  List<String> l = m.get(keys[i]);
                  if (l == null) {
!                     l = new ArrayList<String>();
                      m.put(keys[i], l);
                  }
                  l.add(values[i]);
              } else {
                  // reset the flag
--- 258,268 ----
                  }
              }
              if (!skipIt) {
                  List<String> l = m.get(keys[i]);
                  if (l == null) {
!                     l = new ArrayList<>();
                      m.put(keys[i], l);
                  }
                  l.add(values[i]);
              } else {
                  // reset the flag
*** 272,282 ****
  
          if (include != null) {
                  for (Map.Entry<String,List<String>> entry: include.entrySet()) {
                  List<String> l = m.get(entry.getKey());
                  if (l == null) {
!                     l = new ArrayList<String>();
                      m.put(entry.getKey(), l);
                  }
                  l.addAll(entry.getValue());
              }
          }
--- 272,282 ----
  
          if (include != null) {
                  for (Map.Entry<String,List<String>> entry: include.entrySet()) {
                  List<String> l = m.get(entry.getKey());
                  if (l == null) {
!                     l = new ArrayList<>();
                      m.put(entry.getKey(), l);
                  }
                  l.addAll(entry.getValue());
              }
          }