update use of deprecated ObjectNode.fields() method

config/src/main/java/org/hyperledger/besu/config/GenesisReader.java

@@ -74,7 +74,8 @@ public ObjectNode getConfig() {
 
     @Override
     public Stream<GenesisAccount> streamAllocations() {
-      return Streams.stream(allocations.fields())
+      return allocations
+          .propertyStream()
           .map(
               entry -> {
                 final var on = normalizeKeys((ObjectNode) entry.getValue());
@@ -233,7 +234,8 @@ static Map<UInt256, UInt256> getStorageMap(final ObjectNode json, final String k
       return JsonUtil.getObjectNode(json, key)
           .map(
               storageMap ->
-                  Streams.stream(storageMap.fields())
+                  storageMap
+                      .propertyStream()
                       .collect(
                           Collectors.toMap(
                               e -> UInt256.fromHexString(e.getKey()),

config/src/main/java/org/hyperledger/besu/config/JsonUtil.java

@@ -77,8 +77,8 @@ public static ObjectNode normalizeKeys(
       final ObjectNode objectNode, final Predicate<Map.Entry<String, JsonNode>> fieldPredicate) {
     final ObjectNode normalized = JsonUtil.createEmptyObjectNode();
     objectNode
-        .fields()
-        .forEachRemaining(
+        .propertyStream()
+        .forEach(
             entry -> {
               if (!fieldPredicate.test(entry)) {
                 return;

ethereum/referencetests/src/reference-test/java/org/hyperledger/besu/ethereum/mainnet/DifficultyCalculatorTests.java

@@ -134,27 +134,24 @@ public void testDifficultyCalculation(final String testFile, final ProtocolSched
                 DifficultyCalculatorTests.class.getResource(testFile), StandardCharsets.UTF_8));
 
     if (testObject.size() == 1) {
-      final var topObjectIterator = testObject.fields();
-      while (topObjectIterator.hasNext()) {
-        final Map.Entry<String, JsonNode> testNameIterator = topObjectIterator.next();
-        final var testHolderIter = testNameIterator.getValue().fields();
-        while (testHolderIter.hasNext()) {
-          final var testList = testHolderIter.next();
-          if (!testList.getKey().equals("_info")) {
-            testDifficulty(testFile, protocolSchedule, blockHeaderFunctions, (ObjectNode) testList.getValue());
-          }
-        }
-      }
+      testObject.propertyStream()
+          .forEach(testNameIterator -> {
+            ((ObjectNode) testNameIterator.getValue()).propertyStream()
+                .forEach(testList -> {
+                  if (!testList.getKey().equals("_info")) {
+                    testDifficulty(testFile, protocolSchedule, blockHeaderFunctions, (ObjectNode) testList.getValue());
+                  }
+                });
+          });
     } else {
       testDifficulty(testFile, protocolSchedule, blockHeaderFunctions, testObject);
     }
   }
 
   private void testDifficulty(
       final String testFile, final ProtocolSchedule protocolSchedule, final MainnetBlockHeaderFunctions blockHeaderFunctions, final ObjectNode testObject) {
-    final var fields = testObject.fields();
-    while (fields.hasNext()) {
-      final var entry = fields.next();
+    testObject.propertyStream()
+        .forEach(entry -> {
       final JsonNode value = entry.getValue();
       final long currentBlockNumber = extractLong(value, "currentBlockNumber");
       String parentUncles = value.get("parentUncles").asText();
@@ -188,7 +185,7 @@ private void testDifficulty(
       assertThat(UInt256.valueOf(calculator.nextDifficulty(currentTime, testHeader)))
           .describedAs("File %s Test %s", testFile, entry.getKey())
           .isEqualTo(currentDifficulty);
-    }
+        });
   }
 
   private long extractLong(final JsonNode node, final String name) {