diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 2fec97d6129..3d5a809b6d2 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -271,6 +271,10 @@ led to the suppression of exceptions. (Andrey Bozhko)
 
 * SOLR-17577: Remove "solr.indexfetcher.sotimeout" system property that was for optimizing replication tests.  It was disabled, but not removed. (Eric Pugh)
 
+* SOLR-14680: NamedList: deprecating methods: forEachEntry, forEachKey, abortableForEachKey, abortableForEach,
+ asMap (no-arg only), get(key, default).  Added getOrDefault.  Deprecated the SimpleMap interface as well as the
+ entirety of the SolrJ package org.apache.solr.cluster.api, which wasn't used except for SimpleMap.  (David Smiley)
+
 ==================  9.7.1 ==================
 Bug Fixes
 ---------------------
diff --git a/solr/core/src/java/org/apache/solr/cli/ApiTool.java b/solr/core/src/java/org/apache/solr/cli/ApiTool.java
index ede4de68971..c187360061f 100644
--- a/solr/core/src/java/org/apache/solr/cli/ApiTool.java
+++ b/solr/core/src/java/org/apache/solr/cli/ApiTool.java
@@ -98,7 +98,7 @@ protected String callGet(String url, String credentials) throws Exception {
       NamedList<Object> response = solrClient.request(req);
       // pretty-print the response to stdout
       CharArr arr = new CharArr();
-      new JSONWriter(arr, 2).write(response.asMap());
+      new JSONWriter(arr, 2).write(response.asMap(10));
       return arr.toString();
     }
   }
diff --git a/solr/core/src/java/org/apache/solr/cli/CLIUtils.java b/solr/core/src/java/org/apache/solr/cli/CLIUtils.java
index 7f4c0dc648b..b3336eb2361 100644
--- a/solr/core/src/java/org/apache/solr/cli/CLIUtils.java
+++ b/solr/core/src/java/org/apache/solr/cli/CLIUtils.java
@@ -328,7 +328,7 @@ public static boolean safeCheckCoreExists(String solrUrl, String coreName, Strin
         Map<String, Object> failureStatus =
             (Map<String, Object>) existsCheckResult.get("initFailures");
         String errorMsg = (String) failureStatus.get(coreName);
-        final boolean hasName = coreStatus != null && coreStatus.asMap().containsKey(NAME);
+        final boolean hasName = coreStatus != null && coreStatus.get(NAME) != null;
         exists = hasName || errorMsg != null;
         wait = hasName && errorMsg == null && "true".equals(coreStatus.get("isLoading"));
       } while (wait && System.nanoTime() - startWaitAt < MAX_WAIT_FOR_CORE_LOAD_NANOS);
diff --git a/solr/core/src/java/org/apache/solr/cli/CreateTool.java b/solr/core/src/java/org/apache/solr/cli/CreateTool.java
index b1607af071b..8c46bc13c4f 100644
--- a/solr/core/src/java/org/apache/solr/cli/CreateTool.java
+++ b/solr/core/src/java/org/apache/solr/cli/CreateTool.java
@@ -22,7 +22,6 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Locale;
-import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import org.apache.commons.cli.CommandLine;
@@ -167,10 +166,9 @@ protected void createCore(CommandLine cli, SolrClient solrClient) throws Excepti
 
     String coreRootDirectory; // usually same as solr home, but not always
 
-    Map<String, Object> systemInfo =
-        solrClient
-            .request(new GenericSolrRequest(SolrRequest.METHOD.GET, CommonParams.SYSTEM_INFO_PATH))
-            .asMap();
+    NamedList<?> systemInfo =
+        solrClient.request(
+            new GenericSolrRequest(SolrRequest.METHOD.GET, CommonParams.SYSTEM_INFO_PATH));
 
     // convert raw JSON into user-friendly output
     coreRootDirectory = (String) systemInfo.get("core_root");
@@ -321,7 +319,7 @@ protected void createCollection(CloudSolrClient cloudSolrClient, CommandLine cli
     if (isVerbose()) {
       // pretty-print the response to stdout
       CharArr arr = new CharArr();
-      new JSONWriter(arr, 2).write(response.asMap());
+      new JSONWriter(arr, 2).write(response.asMap(10));
       echo(arr.toString());
     }
     String endMessage =
diff --git a/solr/core/src/java/org/apache/solr/cli/DeleteTool.java b/solr/core/src/java/org/apache/solr/cli/DeleteTool.java
index 7fc94cb85d3..c06e5ddf63c 100644
--- a/solr/core/src/java/org/apache/solr/cli/DeleteTool.java
+++ b/solr/core/src/java/org/apache/solr/cli/DeleteTool.java
@@ -211,7 +211,7 @@ protected void deleteCollection(CloudSolrClient cloudSolrClient, CommandLine cli
     if (isVerbose() && response != null) {
       // pretty-print the response to stdout
       CharArr arr = new CharArr();
-      new JSONWriter(arr, 2).write(response.asMap());
+      new JSONWriter(arr, 2).write(response.asMap(10));
       echo(arr.toString());
       echo("\n");
     }
diff --git a/solr/core/src/java/org/apache/solr/cli/StatusTool.java b/solr/core/src/java/org/apache/solr/cli/StatusTool.java
index 45713fbc085..fa6c2cbf2bd 100644
--- a/solr/core/src/java/org/apache/solr/cli/StatusTool.java
+++ b/solr/core/src/java/org/apache/solr/cli/StatusTool.java
@@ -346,13 +346,14 @@ protected Map<String, String> getCloudStatus(SolrClient solrClient, String zkHos
     Map<String, String> cloudStatus = new LinkedHashMap<>();
     cloudStatus.put("ZooKeeper", (zkHost != null) ? zkHost : "?");
 
+    // TODO add booleans to request just what we want; not everything
     NamedList<Object> json = solrClient.request(new CollectionAdminRequest.ClusterStatus());
 
     List<String> liveNodes = (List<String>) json.findRecursive("cluster", "live_nodes");
     cloudStatus.put("liveNodes", String.valueOf(liveNodes.size()));
 
-    Map<String, Object> collections =
-        ((NamedList<Object>) json.findRecursive("cluster", "collections")).asMap();
+    // TODO get this as a metric from the metrics API instead, or something else.
+    var collections = (NamedList<Object>) json.findRecursive("cluster", "collections");
     cloudStatus.put("collections", String.valueOf(collections.size()));
 
     return cloudStatus;
diff --git a/solr/core/src/java/org/apache/solr/core/OverlaidConfigNode.java b/solr/core/src/java/org/apache/solr/core/OverlaidConfigNode.java
index 30561311dfc..c6fab13fef7 100644
--- a/solr/core/src/java/org/apache/solr/core/OverlaidConfigNode.java
+++ b/solr/core/src/java/org/apache/solr/core/OverlaidConfigNode.java
@@ -19,9 +19,9 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.function.Function;
 import java.util.function.Predicate;
-import org.apache.solr.cluster.api.SimpleMap;
 import org.apache.solr.common.ConfigNode;
 
 /** A config node impl which has an overlay */
@@ -80,7 +80,7 @@ public String name() {
   }
 
   @Override
-  public SimpleMap<String> attributes() {
+  public Map<String, String> attributes() {
     return delegate.attributes();
   }
 
diff --git a/solr/core/src/java/org/apache/solr/core/PluginInfo.java b/solr/core/src/java/org/apache/solr/core/PluginInfo.java
index c091beea08e..2e1991973df 100644
--- a/solr/core/src/java/org/apache/solr/core/PluginInfo.java
+++ b/solr/core/src/java/org/apache/solr/core/PluginInfo.java
@@ -118,7 +118,7 @@ public PluginInfo(ConfigNode node, String err, boolean requireName, boolean requ
     className = cName.className;
     pkgName = cName.pkg;
     initArgs = DOMUtil.childNodesToNamedList(node);
-    attributes = node.attributes().asMap();
+    attributes = node.attributes();
     children = loadSubPlugins(node);
     isFromSolrConfig = true;
   }
diff --git a/solr/core/src/java/org/apache/solr/core/SolrXmlConfig.java b/solr/core/src/java/org/apache/solr/core/SolrXmlConfig.java
index da4df722c59..3525fd2cc95 100644
--- a/solr/core/src/java/org/apache/solr/core/SolrXmlConfig.java
+++ b/solr/core/src/java/org/apache/solr/core/SolrXmlConfig.java
@@ -31,6 +31,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Properties;
 import java.util.Set;
 import java.util.function.Consumer;
@@ -131,10 +132,10 @@ public static NodeConfig fromConfig(
     // since it is arranged as a separate section it is placed here
     Map<String, String> coreAdminHandlerActions =
         readNodeListAsNamedList(root.get("coreAdminHandlerActions"), "<coreAdminHandlerActions>")
-            .asMap()
+            .asShallowMap()
             .entrySet()
             .stream()
-            .collect(Collectors.toMap(item -> item.getKey(), item -> item.getValue().toString()));
+            .collect(Collectors.toMap(Entry::getKey, item -> item.getValue().toString()));
 
     UpdateShardHandlerConfig updateConfig;
     if (deprecatedUpdateConfig == null) {
@@ -733,7 +734,7 @@ private static MetricsConfig getMetricsConfig(ConfigNode metrics) {
     ConfigNode caching = metrics.get("solr/metrics/caching");
     if (caching != null) {
       Object threadsCachingIntervalSeconds =
-          DOMUtil.childNodesToNamedList(caching).get("threadsIntervalSeconds", null);
+          DOMUtil.childNodesToNamedList(caching).get("threadsIntervalSeconds");
       builder.setCacheConfig(
           new MetricsConfig.CacheConfig(
               threadsCachingIntervalSeconds == null
diff --git a/solr/core/src/java/org/apache/solr/schema/IndexSchema.java b/solr/core/src/java/org/apache/solr/schema/IndexSchema.java
index 9cd757571fd..6f4f131de8f 100644
--- a/solr/core/src/java/org/apache/solr/schema/IndexSchema.java
+++ b/solr/core/src/java/org/apache/solr/schema/IndexSchema.java
@@ -526,7 +526,7 @@ protected void readSchema(ConfigSetService.ConfigResource is) {
         log.info("{}", sb);
       }
 
-      version = Float.parseFloat(rootNode.attributes().get("version", "1.0f"));
+      version = Float.parseFloat(rootNode.attributes().getOrDefault("version", "1.0f"));
 
       // load the Field Types
       final FieldTypePluginLoader typeLoader =
diff --git a/solr/core/src/java/org/apache/solr/search/CacheConfig.java b/solr/core/src/java/org/apache/solr/search/CacheConfig.java
index 83ce72af836..da05152a86d 100644
--- a/solr/core/src/java/org/apache/solr/search/CacheConfig.java
+++ b/solr/core/src/java/org/apache/solr/search/CacheConfig.java
@@ -87,7 +87,7 @@ public static Map<String, CacheConfig> getMultipleConfigs(
     for (ConfigNode node : nodes) {
       if (node.boolAttr("enabled", true)) {
         CacheConfig config =
-            getConfig(loader, solrConfig, node.name(), node.attributes().asMap(), configPath);
+            getConfig(loader, solrConfig, node.name(), node.attributes(), configPath);
         result.put(config.args.get(NAME), config);
       }
     }
@@ -98,7 +98,7 @@ public static CacheConfig getConfig(SolrConfig solrConfig, ConfigNode node, Stri
     if (!node.boolAttr("enabled", true) || !node.exists()) {
       return null;
     }
-    return getConfig(solrConfig, node.name(), node.attributes().asMap(), xpath);
+    return getConfig(solrConfig, node.name(), node.attributes(), xpath);
   }
 
   public static CacheConfig getConfig(
diff --git a/solr/core/src/java/org/apache/solr/update/UpdateLog.java b/solr/core/src/java/org/apache/solr/update/UpdateLog.java
index 8e0126073d2..60615a32f49 100644
--- a/solr/core/src/java/org/apache/solr/update/UpdateLog.java
+++ b/solr/core/src/java/org/apache/solr/update/UpdateLog.java
@@ -391,7 +391,8 @@ public void init(PluginInfo info) {
     }
     int timeoutMs =
         objToInt(
-            info.initArgs.get("docLockTimeoutMs", info.initArgs.get("versionBucketLockTimeoutMs")),
+            info.initArgs.getOrDefault(
+                "docLockTimeoutMs", info.initArgs.get("versionBucketLockTimeoutMs")),
             EnvUtils.getPropertyAsLong("solr.update.docLockTimeoutMs", 0L).intValue());
     updateLocks = new UpdateLocks(timeoutMs);
 
diff --git a/solr/core/src/java/org/apache/solr/util/DOMConfigNode.java b/solr/core/src/java/org/apache/solr/util/DOMConfigNode.java
index f7a47b5cc93..d35cd4bccc5 100644
--- a/solr/core/src/java/org/apache/solr/util/DOMConfigNode.java
+++ b/solr/core/src/java/org/apache/solr/util/DOMConfigNode.java
@@ -18,14 +18,11 @@
 package org.apache.solr.util;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
-import org.apache.solr.cluster.api.SimpleMap;
 import org.apache.solr.common.ConfigNode;
 import org.apache.solr.common.util.DOMUtil;
-import org.apache.solr.common.util.WrappedSimpleMap;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
@@ -33,7 +30,7 @@
 public class DOMConfigNode implements ConfigNode {
 
   private final Node node;
-  SimpleMap<String> attrs;
+  Map<String, String> attrs;
 
   @Override
   public String name() {
@@ -50,10 +47,10 @@ public DOMConfigNode(Node node) {
   }
 
   @Override
-  public SimpleMap<String> attributes() {
+  public Map<String, String> attributes() {
     if (attrs != null) return attrs;
     Map<String, String> attrs = DOMUtil.toMap(node.getAttributes());
-    return this.attrs = attrs.size() == 0 ? EMPTY : new WrappedSimpleMap<>(attrs);
+    return this.attrs = attrs.isEmpty() ? Map.of() : attrs;
   }
 
   @Override
@@ -85,6 +82,4 @@ public void forEachChild(Function<ConfigNode, Boolean> fun) {
       if (Boolean.FALSE.equals(toContinue)) break;
     }
   }
-
-  private static final SimpleMap<String> EMPTY = new WrappedSimpleMap<>(Collections.emptyMap());
 }
diff --git a/solr/core/src/java/org/apache/solr/util/DataConfigNode.java b/solr/core/src/java/org/apache/solr/util/DataConfigNode.java
index e8a00075031..4711e644cb4 100644
--- a/solr/core/src/java/org/apache/solr/util/DataConfigNode.java
+++ b/solr/core/src/java/org/apache/solr/util/DataConfigNode.java
@@ -17,8 +17,10 @@
 
 package org.apache.solr.util;
 
+import java.util.AbstractMap;
+import java.util.AbstractSet;
 import java.util.ArrayList;
-import java.util.Collections;
+import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -26,22 +28,20 @@
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
-import org.apache.solr.cluster.api.SimpleMap;
 import org.apache.solr.common.ConfigNode;
 import org.apache.solr.common.util.PropertiesUtil;
-import org.apache.solr.common.util.WrappedSimpleMap;
 
 /** ConfigNode impl that copies and maintains data internally from DOM */
 public class DataConfigNode implements ConfigNode {
   public final String name;
-  public final SimpleMap<String> attributes;
-  public final SimpleMap<List<ConfigNode>> kids;
+  public final Map<String, String> attributes;
+  public final Map<String, List<ConfigNode>> kids;
   public final String textData;
 
   public DataConfigNode(ConfigNode root) {
     Map<String, List<ConfigNode>> kids = new LinkedHashMap<>();
     name = root.name();
-    attributes = wrap(root.attributes());
+    attributes = wrapSubstituting(root.attributes());
     textData = root.txt();
     root.forEachChild(
         it -> {
@@ -54,31 +54,17 @@ public DataConfigNode(ConfigNode root) {
         e.setValue(List.copyOf(e.getValue()));
       }
     }
-    this.kids = kids.isEmpty() ? EMPTY : new WrappedSimpleMap<>(Map.copyOf(kids));
+    this.kids = Map.copyOf(kids);
   }
 
-  public String subtituteVal(String s) {
+  private static String substituteVal(String s) {
     return PropertiesUtil.substitute(s, SUBSTITUTES.get());
   }
 
-  private SimpleMap<String> wrap(SimpleMap<String> delegate) {
+  /** provides a substitute view, and read-only */
+  private static Map<String, String> wrapSubstituting(Map<String, String> delegate) {
     if (delegate.size() == 0) return delegate; // avoid unnecessary object creation
-    return new SimpleMap<>() {
-      @Override
-      public String get(String key) {
-        return subtituteVal(delegate.get(key));
-      }
-
-      @Override
-      public void forEachEntry(BiConsumer<String, ? super String> fun) {
-        delegate.forEachEntry((k, v) -> fun.accept(k, subtituteVal(v)));
-      }
-
-      @Override
-      public int size() {
-        return delegate.size();
-      }
-    };
+    return new SubstitutingMap(delegate);
   }
 
   @Override
@@ -88,11 +74,11 @@ public String name() {
 
   @Override
   public String txt() {
-    return subtituteVal(textData);
+    return substituteVal(textData);
   }
 
   @Override
-  public SimpleMap<String> attributes() {
+  public Map<String, String> attributes() {
     return attributes;
   }
 
@@ -104,7 +90,7 @@ public ConfigNode child(String name) {
 
   @Override
   public List<ConfigNode> getAll(String name) {
-    return kids.get(name, Collections.emptyList());
+    return kids.getOrDefault(name, List.of());
   }
 
   @Override
@@ -126,7 +112,7 @@ public List<ConfigNode> getAll(Predicate<ConfigNode> test, Set<String> matchName
 
   @Override
   public void forEachChild(Function<ConfigNode, Boolean> fun) {
-    kids.forEachEntry(
+    kids.forEach(
         (s, configNodes) -> {
           if (configNodes != null) {
             configNodes.forEach(fun::apply);
@@ -134,6 +120,74 @@ public void forEachChild(Function<ConfigNode, Boolean> fun) {
         });
   }
 
-  public static final SimpleMap<List<ConfigNode>> EMPTY =
-      new WrappedSimpleMap<>(Collections.emptyMap());
+  private static class SubstitutingMap extends AbstractMap<String, String> {
+
+    private final Map<String, String> delegate;
+
+    SubstitutingMap(Map<String, String> delegate) {
+      this.delegate = delegate;
+    }
+
+    @Override
+    public String get(Object key) {
+      return substituteVal(delegate.get(key));
+    }
+
+    @Override
+    public int size() {
+      return delegate.size();
+    }
+
+    @Override
+    public Set<String> keySet() {
+      return delegate.keySet();
+    }
+
+    @Override
+    public void forEach(BiConsumer<? super String, ? super String> action) {
+      delegate.forEach((k, v) -> action.accept(k, substituteVal(v)));
+    }
+
+    @Override
+    public Set<Entry<String, String>> entrySet() {
+      return new AbstractSet<>() {
+        @Override
+        public Iterator<Entry<String, String>> iterator() {
+          // using delegate, return an iterator using Streams
+          return delegate.entrySet().stream()
+              .map(entry -> (Entry<String, String>) new SubstitutingEntry(entry))
+              .iterator();
+        }
+
+        @Override
+        public int size() {
+          return delegate.size();
+        }
+      };
+    }
+
+    private static class SubstitutingEntry implements Entry<String, String> {
+
+      private final Entry<String, String> delegateEntry;
+
+      SubstitutingEntry(Entry<String, String> delegateEntry) {
+        this.delegateEntry = delegateEntry;
+      }
+
+      @Override
+      public String getKey() {
+        return delegateEntry.getKey();
+      }
+
+      @Override
+      public String getValue() {
+        return substituteVal(delegateEntry.getValue());
+      }
+
+      @Override
+      public String setValue(String value) {
+        throw new UnsupportedOperationException();
+      }
+    }
+  }
 }
diff --git a/solr/core/src/test/org/apache/solr/core/TestCodecSupport.java b/solr/core/src/test/org/apache/solr/core/TestCodecSupport.java
index 8fd60619122..54f7406635d 100644
--- a/solr/core/src/test/org/apache/solr/core/TestCodecSupport.java
+++ b/solr/core/src/test/org/apache/solr/core/TestCodecSupport.java
@@ -20,6 +20,7 @@
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.Set;
 import org.apache.lucene.codecs.Codec;
 import org.apache.lucene.codecs.lucene99.Lucene99Codec.Mode;
 import org.apache.lucene.codecs.perfield.PerFieldDocValuesFormat;
@@ -238,7 +239,7 @@ public void testCompressionModeDefault() throws IOException {
         config.get("codecFactory").attr("class"));
     assertTrue(
         "Unexpected configuration of codec factory for this test. Expecting empty element",
-        config.get("codecFactory").getAll(null, (String) null).isEmpty());
+        config.get("codecFactory").getAll(null, Set.of()).isEmpty());
     IndexSchema schema = IndexSchemaFactory.buildIndexSchema("schema_codec.xml", config);
 
     CoreContainer coreContainer = h.getCoreContainer();
diff --git a/solr/core/src/test/org/apache/solr/handler/RequestHandlerMetricsTest.java b/solr/core/src/test/org/apache/solr/handler/RequestHandlerMetricsTest.java
index e3eecfc8cb3..b5b73de2597 100644
--- a/solr/core/src/test/org/apache/solr/handler/RequestHandlerMetricsTest.java
+++ b/solr/core/src/test/org/apache/solr/handler/RequestHandlerMetricsTest.java
@@ -90,11 +90,10 @@ public void testAggregateNodeLevelMetrics() throws SolrServerException, IOExcept
     final double[] minUpdateTime = {Double.MAX_VALUE};
     final double[] maxUpdateTime = {-1.0};
     Set<NamedList<Object>> coreMetrics = new HashSet<>();
-    metrics.forEachKey(
-        (key) -> {
+    metrics.forEach(
+        (key, coreMetric) -> {
           if (key.startsWith("solr.core.testRequestHandlerMetrics")) {
-            NamedList<Object> coreMetric = (NamedList<Object>) metrics.get(key);
-            coreMetrics.add(coreMetric);
+            coreMetrics.add((NamedList<Object>) coreMetric);
           }
         });
     assertEquals(2, coreMetrics.size());
diff --git a/solr/core/src/test/org/apache/solr/handler/admin/CoreAdminHandlerActionTest.java b/solr/core/src/test/org/apache/solr/handler/admin/CoreAdminHandlerActionTest.java
index 235db7af21e..6b5daa5642d 100644
--- a/solr/core/src/test/org/apache/solr/handler/admin/CoreAdminHandlerActionTest.java
+++ b/solr/core/src/test/org/apache/solr/handler/admin/CoreAdminHandlerActionTest.java
@@ -17,7 +17,6 @@
 package org.apache.solr.handler.admin;
 
 import java.util.Locale;
-import java.util.Map;
 import org.apache.solr.SolrTestCaseJ4;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.params.CoreAdminParams;
@@ -82,11 +81,11 @@ private void testAction(String action, String propertyName, String propertyValue
 
     admin.handleRequestBody(req(CoreAdminParams.ACTION, action), response);
 
-    Map<String, Object> actionResponse = ((NamedList<Object>) response.getResponse()).asMap();
+    var actionResponse = (NamedList<Object>) response.getResponse();
 
     assertTrue(
         String.format(Locale.ROOT, "Action response should contain %s property", propertyName),
-        actionResponse.containsKey(propertyName));
+        actionResponse.get(propertyName) != null);
     assertEquals(
         String.format(
             Locale.ROOT,
diff --git a/solr/core/src/test/org/apache/solr/search/facet/SpatialHeatmapFacetsTest.java b/solr/core/src/test/org/apache/solr/search/facet/SpatialHeatmapFacetsTest.java
index 185e9693860..a385eeeb498 100644
--- a/solr/core/src/test/org/apache/solr/search/facet/SpatialHeatmapFacetsTest.java
+++ b/solr/core/src/test/org/apache/solr/search/facet/SpatialHeatmapFacetsTest.java
@@ -155,9 +155,11 @@ public void testClassicFacets() throws Exception { // AKA SimpleFacets
               .findRecursive("facet_counts", "facet_heatmaps", "course", "gridLevel"));
       assertTrue(
           ((NamedList<Object>)
-                  response.getResponse().findRecursive("facet_counts", "facet_heatmaps", "course"))
-              .asMap(0)
-              .containsKey("counts_" + courseFormat));
+                      response
+                          .getResponse()
+                          .findRecursive("facet_counts", "facet_heatmaps", "course"))
+                  .indexOf("counts_" + courseFormat, 0)
+              >= 0);
     }
 
     // ------ Index data
diff --git a/solr/solrj-zookeeper/src/java/org/apache/solr/common/LazySolrCluster.java b/solr/solrj-zookeeper/src/java/org/apache/solr/common/LazySolrCluster.java
index 9b09d063ab2..6dc597ad646 100644
--- a/solr/solrj-zookeeper/src/java/org/apache/solr/common/LazySolrCluster.java
+++ b/solr/solrj-zookeeper/src/java/org/apache/solr/common/LazySolrCluster.java
@@ -53,6 +53,7 @@
  * the value of anything can change any moment Creating an instance is a low cost operation. It does
  * not result in a network call or large object creation
  */
+@Deprecated
 public class LazySolrCluster implements SolrCluster {
   final ZkStateReader zkStateReader;
 
diff --git a/solr/solrj-zookeeper/src/java/org/apache/solr/common/SimpleZkMap.java b/solr/solrj-zookeeper/src/java/org/apache/solr/common/SimpleZkMap.java
index 39051da857c..f72d487256d 100644
--- a/solr/solrj-zookeeper/src/java/org/apache/solr/common/SimpleZkMap.java
+++ b/solr/solrj-zookeeper/src/java/org/apache/solr/common/SimpleZkMap.java
@@ -35,6 +35,7 @@
  * #abortableForEach(BiFunction)} to traverse DO not use the {@link #size()} method. It always
  * return 0 because it is very expensive to compute that
  */
+@Deprecated
 public class SimpleZkMap implements SimpleMap<Resource> {
   private final ZkStateReader zkStateReader;
   private final String basePath;
diff --git a/solr/solrj-zookeeper/src/java/org/apache/solr/common/cloud/PerReplicaStatesOps.java b/solr/solrj-zookeeper/src/java/org/apache/solr/common/cloud/PerReplicaStatesOps.java
index 85fcef00e83..781289df2f7 100644
--- a/solr/solrj-zookeeper/src/java/org/apache/solr/common/cloud/PerReplicaStatesOps.java
+++ b/solr/solrj-zookeeper/src/java/org/apache/solr/common/cloud/PerReplicaStatesOps.java
@@ -212,7 +212,7 @@ public static PerReplicaStatesOps disable(PerReplicaStates rs) {
         new PerReplicaStatesOps(
             prs -> {
               List<PerReplicaStates.Operation> result = new ArrayList<>();
-              prs.states.forEachEntry(
+              prs.states.forEach(
                   (s, state) ->
                       result.add(
                           new PerReplicaStates.Operation(
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/ApiType.java b/solr/solrj/src/java/org/apache/solr/cluster/api/ApiType.java
index 1d4502cd3ce..1945a2039a1 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/ApiType.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/ApiType.java
@@ -18,6 +18,7 @@
 package org.apache.solr.cluster.api;
 
 /** Types of API calls */
+@Deprecated
 public enum ApiType {
   V1("solr"),
   V2("api");
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/CollectionConfig.java b/solr/solrj/src/java/org/apache/solr/cluster/api/CollectionConfig.java
index 020c57fc055..c3043ab50dc 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/CollectionConfig.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/CollectionConfig.java
@@ -17,6 +17,7 @@
 
 package org.apache.solr.cluster.api;
 
+@Deprecated
 public interface CollectionConfig {
 
   String name();
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/HashRange.java b/solr/solrj/src/java/org/apache/solr/cluster/api/HashRange.java
index 23d8fab1325..3bfa66eaab6 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/HashRange.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/HashRange.java
@@ -18,6 +18,7 @@
 package org.apache.solr.cluster.api;
 
 /** A range of hash that is stored in a shard */
+@Deprecated
 public interface HashRange {
 
   /** minimum value (inclusive) */
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/Resource.java b/solr/solrj/src/java/org/apache/solr/cluster/api/Resource.java
index 13548f6a822..faa5207838b 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/Resource.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/Resource.java
@@ -22,6 +22,7 @@
 import org.apache.solr.common.SolrException;
 
 /** A binary resource. The impl is agnostic of the content type */
+@Deprecated
 public interface Resource {
   /** This is a full path. e.g schema.xml, solrconfig.xml, lang/stopwords.txt etc */
   String name();
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/Router.java b/solr/solrj/src/java/org/apache/solr/cluster/api/Router.java
index ae6f6336ba4..ecea98572f2 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/Router.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/Router.java
@@ -18,6 +18,7 @@
 package org.apache.solr.cluster.api;
 
 /** identify shards for a given routing key or document id */
+@Deprecated
 public interface Router {
 
   /** shard name for a given routing key */
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/Shard.java b/solr/solrj/src/java/org/apache/solr/cluster/api/Shard.java
index 0b3cfc15abd..896cf8dd6b4 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/Shard.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/Shard.java
@@ -18,6 +18,7 @@
 package org.apache.solr.cluster.api;
 
 /** A shard of a collection */
+@Deprecated
 public interface Shard {
 
   /** name of the shard */
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/ShardReplica.java b/solr/solrj/src/java/org/apache/solr/cluster/api/ShardReplica.java
index 57b133a0ad6..0e85e51cea7 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/ShardReplica.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/ShardReplica.java
@@ -20,6 +20,7 @@
 import org.apache.solr.common.cloud.Replica;
 
 /** replica of a shard */
+@Deprecated
 public interface ShardReplica {
   /** Name of this replica */
   String name();
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/SimpleMap.java b/solr/solrj/src/java/org/apache/solr/cluster/api/SimpleMap.java
index 4398d12742f..3684a2862df 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/SimpleMap.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/SimpleMap.java
@@ -32,23 +32,27 @@
  * efficient to implement and consume. The keys are always {@link CharSequence} objects, The values
  * can be of any type
  */
+@Deprecated
 public interface SimpleMap<T> extends MapWriter {
 
   /** get a value by key. If not present , null is returned */
   T get(String key);
 
+  @Deprecated
   default T get(String key, T def) {
     T val = get(key);
     return val == null ? def : val;
   }
 
   /** Navigate through all keys and values */
+  @Deprecated
   void forEachEntry(BiConsumer<String, ? super T> fun);
 
   /**
    * iterate through all keys The default impl is suboptimal. Proper implementations must do it more
    * efficiently
    */
+  @Deprecated
   default void forEachKey(Consumer<String> fun) {
     forEachEntry((k, t) -> fun.accept(k));
   }
@@ -62,6 +66,7 @@ default void forEachKey(Consumer<String> fun) {
    * @param fun Consume each key and return a boolean to signal whether to proceed or not. If true,
    *     continue. If false stop
    */
+  @Deprecated
   default void abortableForEachKey(Function<String, Boolean> fun) {
     abortableForEach((key, t) -> fun.apply(key));
   }
@@ -73,6 +78,7 @@ default void abortableForEachKey(Function<String, Boolean> fun) {
    * @param fun Consume each entry and return a boolean to signal whether to proceed or not. If
    *     true, continue, if false stop
    */
+  @Deprecated
   default void abortableForEach(BiFunction<String, ? super T, Boolean> fun) {
     forEachEntry(
         new BiConsumer<>() {
@@ -91,11 +97,13 @@ default void writeMap(EntryWriter ew) throws IOException {
     forEachEntry(ew::putNoEx);
   }
 
+  @Deprecated
   default Map<String, T> asMap(Map<String, T> sink) {
     forEachEntry(sink::put);
     return sink;
   }
 
+  @Deprecated
   default Map<String, T> asMap() {
     return asMap(new LinkedHashMap<>());
   }
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCluster.java b/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCluster.java
index 301cd57655b..1fa77d24c8d 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCluster.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCluster.java
@@ -20,6 +20,7 @@
 import org.apache.solr.common.SolrException;
 
 /** Represents a Solr cluster */
+@Deprecated
 public interface SolrCluster {
 
   /** collections in the cluster */
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCollection.java b/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCollection.java
index df9007e3b7f..c0dd86d047a 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCollection.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/SolrCollection.java
@@ -18,6 +18,7 @@
 package org.apache.solr.cluster.api;
 
 /** Represents a collection in Solr */
+@Deprecated
 public interface SolrCollection {
 
   String name();
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/SolrNode.java b/solr/solrj/src/java/org/apache/solr/cluster/api/SolrNode.java
index 13115643c12..e6db68a1470 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/SolrNode.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/SolrNode.java
@@ -18,6 +18,7 @@
 package org.apache.solr.cluster.api;
 
 /** A read only view of a Solr node */
+@Deprecated
 public interface SolrNode {
 
   /** The node name */
diff --git a/solr/solrj/src/java/org/apache/solr/cluster/api/package-info.java b/solr/solrj/src/java/org/apache/solr/cluster/api/package-info.java
index 9c4183d49da..84e7f43b356 100644
--- a/solr/solrj/src/java/org/apache/solr/cluster/api/package-info.java
+++ b/solr/solrj/src/java/org/apache/solr/cluster/api/package-info.java
@@ -16,4 +16,5 @@
  */
 
 /** API interfaces for core SolrCloud classes */
+@Deprecated
 package org.apache.solr.cluster.api;
diff --git a/solr/solrj/src/java/org/apache/solr/common/ConfigNode.java b/solr/solrj/src/java/org/apache/solr/common/ConfigNode.java
index be86c1e5c7b..18022605f69 100644
--- a/solr/solrj/src/java/org/apache/solr/common/ConfigNode.java
+++ b/solr/solrj/src/java/org/apache/solr/common/ConfigNode.java
@@ -26,12 +26,11 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
-import org.apache.solr.cluster.api.SimpleMap;
-import org.apache.solr.common.util.WrappedSimpleMap;
 
 /**
  * A generic interface that represents a config file, mostly XML Please note that this is an
@@ -44,7 +43,7 @@ public interface ConfigNode {
   String name();
 
   /** Attributes */
-  SimpleMap<String> attributes();
+  Map<String, String> attributes();
 
   /** Child by name */
   default ConfigNode child(String name) {
@@ -195,8 +194,8 @@ public String txt() {
         }
 
         @Override
-        public SimpleMap<String> attributes() {
-          return empty_attrs;
+        public Map<String, String> attributes() {
+          return Map.of();
         }
 
         @Override
@@ -233,8 +232,6 @@ public boolean isNull() {
         public void forEachChild(Function<ConfigNode, Boolean> fun) {}
       };
 
-  SimpleMap<String> empty_attrs = new WrappedSimpleMap<>(Collections.emptyMap());
-
   class Helpers {
     static boolean _bool(Object v, boolean def) {
       return v == null ? def : Boolean.parseBoolean(v.toString());
diff --git a/solr/solrj/src/java/org/apache/solr/common/cloud/DocRouter.java b/solr/solrj/src/java/org/apache/solr/common/cloud/DocRouter.java
index 2ac50b6b1f5..d3a533b07d0 100644
--- a/solr/solrj/src/java/org/apache/solr/common/cloud/DocRouter.java
+++ b/solr/solrj/src/java/org/apache/solr/common/cloud/DocRouter.java
@@ -24,7 +24,6 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import org.apache.solr.cluster.api.HashRange;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.SolrInputDocument;
 import org.apache.solr.common.cloud.DocCollection.CollectionStateProps;
@@ -89,7 +88,7 @@ public static Map<String, Object> getRouterSpec(ZkNodeProps props) {
   // Hash ranges can't currently "wrap" - i.e. max must be greater or equal to min.
   // TODO: ranges may not be all contiguous in the future (either that or we will
   // need an extra class to model a collection of ranges)
-  public static class Range implements JSONWriter.Writable, Comparable<Range>, HashRange {
+  public static class Range implements JSONWriter.Writable, Comparable<Range> {
     public int min; // inclusive
     public int max; // inclusive
 
@@ -99,17 +98,14 @@ public Range(int min, int max) {
       this.max = max;
     }
 
-    @Override
     public int min() {
       return min;
     }
 
-    @Override
     public int max() {
       return max;
     }
 
-    @Override
     public boolean includes(int hash) {
       return hash >= min && hash <= max;
     }
diff --git a/solr/solrj/src/java/org/apache/solr/common/cloud/PerReplicaStates.java b/solr/solrj/src/java/org/apache/solr/common/cloud/PerReplicaStates.java
index e8e95d4e8ea..783729e2edf 100644
--- a/solr/solrj/src/java/org/apache/solr/common/cloud/PerReplicaStates.java
+++ b/solr/solrj/src/java/org/apache/solr/common/cloud/PerReplicaStates.java
@@ -31,14 +31,12 @@
 import java.util.Objects;
 import java.util.Set;
 import java.util.function.BiConsumer;
-import org.apache.solr.cluster.api.SimpleMap;
 import org.apache.solr.common.IteratorWriter;
 import org.apache.solr.common.MapWriter;
 import org.apache.solr.common.annotation.JsonProperty;
 import org.apache.solr.common.cloud.Replica.ReplicaStateProps;
 import org.apache.solr.common.util.ReflectMapWriter;
 import org.apache.solr.common.util.StrUtils;
-import org.apache.solr.common.util.WrappedSimpleMap;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -59,7 +57,7 @@ public class PerReplicaStates implements ReflectMapWriter {
   @JsonProperty public final int cversion;
 
   // states of individual replicas
-  @JsonProperty public final SimpleMap<State> states;
+  @JsonProperty public final Map<String, State> states;
 
   private volatile Boolean allActive;
 
@@ -85,7 +83,7 @@ public PerReplicaStates(String path, int cversion, List<String> states) {
         tmp.put(rs.replica, rs.insert(existing));
       }
     }
-    this.states = new WrappedSimpleMap<>(tmp);
+    this.states = tmp;
   }
 
   public static PerReplicaStates empty(String collectionName) {
@@ -95,27 +93,23 @@ public static PerReplicaStates empty(String collectionName) {
   /** Check and return if all replicas are ACTIVE */
   public boolean allActive() {
     if (this.allActive != null) return allActive;
-    boolean[] result = new boolean[] {true};
-    states.forEachEntry(
-        (r, s) -> {
-          if (s.state != Replica.State.ACTIVE) result[0] = false;
-        });
-    return this.allActive = result[0];
+    this.allActive = states.values().stream().allMatch(s -> s.state == Replica.State.ACTIVE);
+    return allActive;
   }
 
   /** Get the changed replicas */
   public static Set<String> findModifiedReplicas(PerReplicaStates old, PerReplicaStates fresh) {
     Set<String> result = new HashSet<>();
     if (fresh == null) {
-      old.states.forEachKey(result::add);
+      result.addAll(old.states.keySet());
       return result;
     }
-    old.states.forEachEntry(
+    old.states.forEach(
         (s, state) -> {
           // the state is modified or missing
           if (!Objects.equals(fresh.get(s), state)) result.add(s);
         });
-    fresh.states.forEachEntry(
+    fresh.states.forEach(
         (s, state) -> {
           if (old.get(s) == null) result.add(s);
         });
@@ -165,8 +159,8 @@ public String toString() {
   }
 
   private StringBuilder appendStates(StringBuilder sb) {
-    states.forEachEntry(
-        new BiConsumer<String, State>() {
+    states.forEach(
+        new BiConsumer<>() {
           int count = 0;
 
           @Override
@@ -317,7 +311,7 @@ public EntryWriter put(CharSequence k, Object v) throws IOException {
               ew.put(
                   "states",
                   (IteratorWriter)
-                      iw -> states.forEachEntry((s, state) -> iw.addNoEx(state.toString())));
+                      iw -> states.forEach((s, state) -> iw.addNoEx(state.toString())));
             } else {
               ew.put(k, v);
             }
diff --git a/solr/solrj/src/java/org/apache/solr/common/util/DOMUtil.java b/solr/solrj/src/java/org/apache/solr/common/util/DOMUtil.java
index 840c64b5d87..0ef6bfbe538 100644
--- a/solr/solrj/src/java/org/apache/solr/common/util/DOMUtil.java
+++ b/solr/solrj/src/java/org/apache/solr/common/util/DOMUtil.java
@@ -50,7 +50,7 @@ public static Map<String, String> toMap(ConfigNode node) {
   public static Map<String, String> toMapExcept(ConfigNode node, String... exclusions) {
     Map<String, String> args = new HashMap<>();
     node.attributes()
-        .forEachEntry(
+        .forEach(
             (k, v) -> {
               for (String ex : exclusions) if (ex.equals(k)) return;
               args.put(k, v);
diff --git a/solr/solrj/src/java/org/apache/solr/common/util/NamedList.java b/solr/solrj/src/java/org/apache/solr/common/util/NamedList.java
index e443414c5b1..123a5e81d91 100644
--- a/solr/solrj/src/java/org/apache/solr/common/util/NamedList.java
+++ b/solr/solrj/src/java/org/apache/solr/common/util/NamedList.java
@@ -253,6 +253,12 @@ public T get(String name) {
     return get(name, 0);
   }
 
+  /** Like {@link #get(String)} but returns a default value if it would be null. */
+  public T getOrDefault(String name, T def) {
+    T val = get(name);
+    return val == null ? def : val;
+  }
+
   /**
    * Gets the value for the first instance of the specified name found starting at the specified
    * index.
@@ -486,7 +492,7 @@ public Set<Entry<String, T>> entrySet() {
 
       @Override
       public void forEach(BiConsumer action) {
-        NamedList.this.forEachEntry(action);
+        NamedList.this.forEach(action);
       }
     };
   }
diff --git a/solr/solrj/src/java/org/apache/solr/common/util/WrappedSimpleMap.java b/solr/solrj/src/java/org/apache/solr/common/util/WrappedSimpleMap.java
index 417e8d3c968..768fef788b9 100644
--- a/solr/solrj/src/java/org/apache/solr/common/util/WrappedSimpleMap.java
+++ b/solr/solrj/src/java/org/apache/solr/common/util/WrappedSimpleMap.java
@@ -22,6 +22,7 @@
 import java.util.function.BiConsumer;
 import org.apache.solr.cluster.api.SimpleMap;
 
+@Deprecated
 public class WrappedSimpleMap<T> implements SimpleMap<T> {
   private final Map<String, T> delegate;
 
diff --git a/solr/solrj/src/test/org/apache/solr/common/cloud/PerReplicaStatesIntegrationTest.java b/solr/solrj/src/test/org/apache/solr/common/cloud/PerReplicaStatesIntegrationTest.java
index 21a5307eb67..71336a8088d 100644
--- a/solr/solrj/src/test/org/apache/solr/common/cloud/PerReplicaStatesIntegrationTest.java
+++ b/solr/solrj/src/test/org/apache/solr/common/cloud/PerReplicaStatesIntegrationTest.java
@@ -164,7 +164,7 @@ public void testRestart() throws Exception {
           PerReplicaStatesOps.fetch(collectionPath, SolrCloudTestCase.cluster.getZkClient(), null);
       assertEquals(2, prs.states.size());
       c = cluster.getZkStateReader().getCollection(testCollection);
-      prs.states.forEachEntry((s, state) -> assertEquals(Replica.State.ACTIVE, state.state));
+      prs.states.forEach((s, state) -> assertEquals(Replica.State.ACTIVE, state.state));
 
       String replicaName = null;
       for (Replica r : c.getSlice("shard1").getReplicas()) {
@@ -226,7 +226,7 @@ public void testRestart() throws Exception {
         prs =
             PerReplicaStatesOps.fetch(
                 collectionPath, SolrCloudTestCase.cluster.getZkClient(), null);
-        prs.states.forEachEntry((s, state) -> assertEquals(Replica.State.ACTIVE, state.state));
+        prs.states.forEach((s, state) -> assertEquals(Replica.State.ACTIVE, state.state));
       }
 
     } finally {
@@ -286,7 +286,7 @@ public void testMultipleTransitions() throws Exception {
                 PerReplicaStates prs2 =
                     PerReplicaStatesOps.fetch(
                         DocCollection.getCollectionPath(COLL), cluster.getZkClient(), null);
-                prs2.states.forEachEntry(
+                prs2.states.forEach(
                     (r, newState) -> {
                       if (newState.getDuplicate() != null) anyFail.set(true);
                     });