From d95b548c78d2c504ccc3044f434f83e5c8237b0e Mon Sep 17 00:00:00 2001
From: Per Minborg <pminborg@openjdk.org>
Date: Thu, 12 Oct 2023 07:51:21 +0000
Subject: [PATCH] 8315850: Improve AbstractMap anonymous Iterator classes

Reviewed-by: liach, smarks
---
 .../share/classes/java/util/AbstractMap.java  | 52 +++++++------------
 1 file changed, 20 insertions(+), 32 deletions(-)

diff --git a/src/java.base/share/classes/java/util/AbstractMap.java b/src/java.base/share/classes/java/util/AbstractMap.java
index 7a5d92bda52..c5ea53e17db 100644
--- a/src/java.base/share/classes/java/util/AbstractMap.java
+++ b/src/java.base/share/classes/java/util/AbstractMap.java
@@ -350,23 +350,9 @@ public abstract class AbstractMap<K,V> implements Map<K,V> {
     public Set<K> keySet() {
         Set<K> ks = keySet;
         if (ks == null) {
-            ks = new AbstractSet<K>() {
+            ks = new AbstractSet<>() {
                 public Iterator<K> iterator() {
-                    return new Iterator<K>() {
-                        private Iterator<Entry<K,V>> i = entrySet().iterator();
-
-                        public boolean hasNext() {
-                            return i.hasNext();
-                        }
-
-                        public K next() {
-                            return i.next().getKey();
-                        }
-
-                        public void remove() {
-                            i.remove();
-                        }
-                    };
+                    return new KeyIterator();
                 }
 
                 public int size() {
@@ -409,23 +395,9 @@ public abstract class AbstractMap<K,V> implements Map<K,V> {
     public Collection<V> values() {
         Collection<V> vals = values;
         if (vals == null) {
-            vals = new AbstractCollection<V>() {
+            vals = new AbstractCollection<>() {
                 public Iterator<V> iterator() {
-                    return new Iterator<V>() {
-                        private Iterator<Entry<K,V>> i = entrySet().iterator();
-
-                        public boolean hasNext() {
-                            return i.hasNext();
-                        }
-
-                        public V next() {
-                            return i.next().getValue();
-                        }
-
-                        public void remove() {
-                            i.remove();
-                        }
-                    };
+                    return new ValueIterator();
                 }
 
                 public int size() {
@@ -924,4 +896,20 @@ public abstract class AbstractMap<K,V> implements Map<K,V> {
         public <T> T[] toArray(T[] a) { return view().toArray(a); }
         public String toString() { return view().toString(); }
     }
+
+    // Iterator implementations.
+
+    final class KeyIterator implements Iterator<K> {
+        private final Iterator<Entry<K,V>> i = entrySet().iterator();
+        public boolean hasNext() { return i.hasNext(); }
+        public void remove() { i.remove(); }
+        public K next() { return i.next().getKey(); }
+    }
+
+    final class ValueIterator implements Iterator<V> {
+        private final Iterator<Entry<K,V>> i = entrySet().iterator();
+        public boolean hasNext() { return i.hasNext(); }
+        public void remove() { i.remove(); }
+        public V next() { return i.next().getValue(); }
+    }
 }