src/java.base/share/classes/sun/util/PreHashedMap.java

*** 164,181 ****
              a = (Object[])a[2];
          }
      }
  
      public Set<String> keySet() {
!         return new AbstractSet<String> () {
  
              public int size() {
                  return size;
              }
  
              public Iterator<String> iterator() {
!                 return new Iterator<String>() {
                      private int i = -1;
                      Object[] a = null;
                      String cur = null;
  
                      private boolean findNext() {
--- 164,181 ----
              a = (Object[])a[2];
          }
      }
  
      public Set<String> keySet() {
!         return new AbstractSet<> () {
  
              public int size() {
                  return size;
              }
  
              public Iterator<String> iterator() {
!                 return new Iterator<>() {
                      private int i = -1;
                      Object[] a = null;
                      String cur = null;
  
                      private boolean findNext() {