epugh · Oct 20, 2026 · Oct 16, 2026 · Oct 16, 2026 · Oct 16, 2026 · Oct 16, 2026
diff --git a/changelog/unreleased/SOLR-16396-config-remaining-get-sections.yml b/changelog/unreleased/SOLR-16396-config-remaining-get-sections.yml
@@ -0,0 +1,13 @@
+title: >
+  Migrate remaining GET /config/{component} sections to JAX-RS.
+  V2 renames listener, queryParser, valueSourceParser, cache, transformer, updateProcessor, queryConverter and expressible to
+  listeners, queryParsers, valueSourceParsers, caches, transformers, updateProcessors, queryConverters and expressibles respectively.  (V1 unchanged)
+type: changed
+authors:
+  - name: Jalaz Kumar
+    nick: jaykay12
+  - name: Eric Pugh
+    nick: epugh
+links:
+  - name: SOLR-16396
+    url: https://issues.apache.org/jira/browse/SOLR-16396
diff --git a/solr/api/src/java/org/apache/solr/client/api/endpoint/ConfigApi.java b/solr/api/src/java/org/apache/solr/client/api/endpoint/ConfigApi.java
@@ -91,12 +91,10 @@ ConfigInfoResponse getRequestHandler(
             @Parameter(description = "Include package metadata (_packageinfo_)")
             boolean meta);
 
-    // TODO: Keep this regex in sync with GetConfig.MIGRATED_CONFIG_COMPONENTS ("searchComponents"
-    // and "queryResponseWriters" here are the external, pluralized names for the internal
-    // "searchComponent"/"queryResponseWriter" sections; see GetConfig#toExternalComponentName)
+    // TODO: Keep this regex in sync with GetConfig.MIGRATED_CONFIG_COMPONENTS
     @GET
     @Path(
-        "/{component:updateHandler|directoryFactory|indexConfig|codecFactory|query|searchComponents|queryResponseWriters}")
+        "/{component:updateHandler|directoryFactory|indexConfig|codecFactory|query|searchComponents|queryResponseWriters|luceneMatchVersion|initParams|listeners|requestDispatcher|jmx|queryParsers|valueSourceParsers|transformers|updateProcessors|updateRequestProcessorChain|queryConverters|caches|circuitBreaker|expressibles|schemaFactory|restManager|statsCache|recoveryStrategy|indexReaderFactory|indexConfigdeletionPolicy|updateHandlerupdateLog}")
     @StoreApiParameters
     @Operation(
         summary = "Fetch a config section",
@@ -105,12 +103,15 @@ ConfigInfoResponse getConfigComponent(
         @PathParam("component") @Parameter(description = "Name of the config component")
             String component);
 
-    // TODO: Keep this regex in sync with GetConfig.MIGRATED_CONFIG_COMPONENTS ("searchComponents"
-    // and "queryResponseWriters" here are the external, pluralized names for the internal
-    // "searchComponent"/"queryResponseWriter" sections; see GetConfig#toExternalComponentName)
+    // TODO: Keep this regex in sync with GetConfig.MIGRATED_CONFIG_COMPONENTS. Sections without
+    // REQUIRE_NAME in SolrConfig's plugin registration (initParams, listeners,
+    // updateRequestProcessorChain, circuitBreaker) are deliberately excluded here: they're
+    // serialized as a List rather than a name-keyed Map, so by-name lookup isn't meaningful for
+    // them (see GetConfig.filterByComponentName).
+    // Scalars / non-plugin sections (luceneMatchVersion, jmx etc) are also omitted.
     @GET
     @Path(
-        "/{component:updateHandler|directoryFactory|indexConfig|codecFactory|query|searchComponents|queryResponseWriters}/{componentName}")
+        "/{component:updateHandler|directoryFactory|indexConfig|codecFactory|query|searchComponents|queryResponseWriters|queryParsers|valueSourceParsers|transformers|updateProcessors|queryConverters|caches|expressibles|schemaFactory|restManager|statsCache|recoveryStrategy|indexReaderFactory}/{componentName}")
     @StoreApiParameters
     @Operation(
         summary = "Fetch a single named entry within a config section",

diff --git a/solr/core/src/java/org/apache/solr/handler/SolrConfigHandler.java b/solr/core/src/java/org/apache/solr/handler/SolrConfigHandler.java
@@ -237,16 +237,9 @@ private void handleGET() {
                     : getConfig.getConfigComponentByName(
                         parts.get(1), componentName, req.getParams().getBool("meta", false)));
           } else {
-            Map<String, Object> m =
-                Utils.convertToMap(req.getCore().getSolrConfig(), new LinkedHashMap<>());
-            Map<String, Object> val = new LinkedHashMap<>();
-            val.put(parts.get(1), m.get(parts.get(1)));
-            String componentName = req.getParams().get("componentName");
-            if (componentName != null) {
-              GetConfig.filterByComponentName(
-                  val, parts.get(1), componentName, req.getParams().getBool("meta", false), req);
-            }
-            resp.add("config", val);
+            throw new SolrException(
+                SolrException.ErrorCode.NOT_FOUND,
+                "No config API for path: /config/" + parts.get(1));
           }
         }
       }

diff --git a/solr/core/src/java/org/apache/solr/handler/admin/api/GetConfig.java b/solr/core/src/java/org/apache/solr/handler/admin/api/GetConfig.java
@@ -67,7 +67,28 @@ public class GetConfig extends JerseyResource implements ConfigApi.Get {
           "codecFactory",
           "query",
           "searchComponent",
-          "queryResponseWriter");
+          "queryResponseWriter",
+          "luceneMatchVersion",
+          "initParams",
+          "listener",
+          "requestDispatcher",
+          "jmx",
+          "queryParser",
+          "valueSourceParser",
+          "transformer",
+          "updateProcessor",
+          "updateRequestProcessorChain",
+          "queryConverter",
+          "cache",
+          "circuitBreaker",
+          "expressible",
+          "schemaFactory",
+          "restManager",
+          "statsCache",
+          "recoveryStrategy",
+          "indexReaderFactory",
+          "indexConfigdeletionPolicy",
+          "updateHandlerupdateLog");
 
   public static final String REQUEST_HANDLERS = "requestHandlers";
 
@@ -77,7 +98,15 @@ public class GetConfig extends JerseyResource implements ConfigApi.Get {
   private static final Map<String, String> EXTERNAL_TO_INTERNAL_COMPONENT_NAME =
       Map.of(
           "searchComponents", "searchComponent",
-          "queryResponseWriters", "queryResponseWriter");
+          "queryResponseWriters", "queryResponseWriter",
+          "listeners", "listener",
+          "queryParsers", "queryParser",
+          "valueSourceParsers", "valueSourceParser",
+          "transformers", "transformer",
+          "updateProcessors", "updateProcessor",
+          "queryConverters", "queryConverter",
+          "expressibles", "expressible",
+          "caches", "cache");
 
   // Same, but for the full /config dump's top-level keys, which also renames requestHandler.
   // Derived from the map above so the two can't drift apart.
@@ -239,10 +268,16 @@ public static void filterByComponentName(
       String componentName,
       boolean meta,
       SolrQueryRequest req) {
-    Map pluginNameVsPluginInfo = (Map) configMap.get(component);
-    if (pluginNameVsPluginInfo == null) {
+    Object sectionValue = configMap.get(component);
+    if (sectionValue == null) {
       return;
     }
+    if (!(sectionValue instanceof Map) && !(sectionValue instanceof MapWriter)) {
+      throw new SolrException(
+          SolrException.ErrorCode.NOT_FOUND,
+          component + " does not support filtering by componentName");
+    }
+    Map pluginNameVsPluginInfo = (Map) sectionValue;
 
     Object o =
         pluginNameVsPluginInfo instanceof MapWriter
@@ -335,7 +370,7 @@ private Map<String, Object> requestHandlersWithImplicits(
     return reqHandlersMap;
   }
 
-  @SuppressWarnings({"unchecked", "rawtypes"})
+  @SuppressWarnings("unchecked")
   private Map<String, Object> expandUseParams(SolrQueryRequest req, Object plugin) {
     Map<String, Object> pluginInfo;
     if (plugin instanceof Map) {

diff --git a/solr/core/src/java/org/apache/solr/handler/admin/api/GetConfigAPI.java b/solr/core/src/java/org/apache/solr/handler/admin/api/GetConfigAPI.java
@@ -28,9 +28,8 @@
 /**
  * V2 APIs for retrieving some or all configuration relevant to a particular collection (or core).
  *
- * <p>This class covers legacy AnnotatedApi paths under GET /config: /params, /params{paramset}, and
- * remaining {@code /config/{component}} sections not yet migrated to {@link
- * org.apache.solr.client.api.endpoint.ConfigApi.Get}
+ * <p>This class only covers legacy AnnotatedApi paths under GET /config: /params and
+ * /params{paramset}
  */
 public class GetConfigAPI {
   private final SolrConfigHandler configHandler;
@@ -54,37 +53,4 @@ public void getAllParamSets(SolrQueryRequest req, SolrQueryResponse rsp) {
   public void getSingleParamSet(SolrQueryRequest req, SolrQueryResponse rsp) {
     configHandler.handleRequest(req, rsp);
   }
-
-  // GET /config/... sections still via SolrConfigHandler.
-  // Every name SolrConfig.writeMap can emit.
-  // Delete a path from this list when that section is migrated to Jersey
-  @EndPoint(
-      path = {
-        "/config/luceneMatchVersion",
-        "/config/initParams",
-        "/config/listener",
-        "/config/requestDispatcher",
-        "/config/jmx",
-        "/config/queryParser",
-        "/config/valueSourceParser",
-        "/config/transformer",
-        "/config/updateProcessor",
-        "/config/updateRequestProcessorChain",
-        "/config/queryConverter",
-        "/config/cache",
-        "/config/circuitBreaker",
-        "/config/expressible",
-        "/config/schemaFactory",
-        "/config/restManager",
-        "/config/statsCache",
-        "/config/recoveryStrategy",
-        "/config/indexReaderFactory",
-        "/config/indexConfigdeletionPolicy",
-        "/config/updateHandlerupdateLog"
-      },
-      method = GET,
-      permission = CONFIG_READ_PERM)
-  public void getComponentConfig(SolrQueryRequest req, SolrQueryResponse rsp) {
-    configHandler.handleRequest(req, rsp);
-  }
 }
diff --git a/solr/core/src/test/org/apache/solr/handler/admin/V2ConfigAPIMappingTest.java b/solr/core/src/test/org/apache/solr/handler/admin/V2ConfigAPIMappingTest.java
@@ -44,18 +44,6 @@ public void populateApiBag() {
     apiBag.registerObject(new ModifyParamSetAPI(getRequestHandler()));
   }
 
-  // GET /v2/collectionName/config/<component> is a pure pass-through to the underlying request
-  // handler.  Just check
-  // the API lookup works for a handful of the valid config "components".
-  @Test
-  public void testGetSingleComponentConfig() {
-    assertAnnotatedApiExistsFor("GET", "/config/jmx");
-    assertAnnotatedApiExistsFor("GET", "/config/requestDispatcher");
-    assertAnnotatedApiExistsFor("GET", "/config/luceneMatchVersion");
-    assertAnnotatedApiExistsFor("GET", "/config/indexConfigdeletionPolicy");
-    assertAnnotatedApiExistsFor("GET", "/config/updateHandlerupdateLog");
-  }
-
   @Test
   public void testGetParamsetsConfig() {
     assertAnnotatedApiExistsFor("GET", "/config/params");

diff --git a/solr/core/src/test/org/apache/solr/handler/admin/api/GetConfigTest.java b/solr/core/src/test/org/apache/solr/handler/admin/api/GetConfigTest.java
@@ -19,6 +19,7 @@
 import static org.apache.solr.core.CoreContainer.ALLOW_PATHS_SYSPROP;
 import static org.apache.solr.handler.admin.api.GetConfig.REQUEST_HANDLERS;
 
+import java.util.List;
 import java.util.Map;
 import org.apache.solr.SolrTestCase;
 import org.apache.solr.client.api.model.IndexType;
@@ -242,6 +243,37 @@ public void testGetConfigComponentFilteredByNameForOtherMigratedComponents() thr
     assertTrue(querySection.containsKey("filterCache"));
   }
 
+  @Test
+  @SuppressWarnings("unchecked")
+  public void testGetConfigComponentSectionShapes() throws Exception {
+    var queryResponse =
+        new ConfigApi.GetConfigComponent(IndexType.CORE, CORE_NAME, "luceneMatchVersion")
+            .process(solrTestRule.getSolrClient(CORE_NAME));
+    assertNull(queryResponse.error);
+    assertTrue(queryResponse.config.get("luceneMatchVersion") instanceof String);
+
+    queryResponse =
+        new ConfigApi.GetConfigComponent(IndexType.CORE, CORE_NAME, "initParams")
+            .process(solrTestRule.getSolrClient(CORE_NAME));
+    assertNull(queryResponse.error);
+    assertTrue(queryResponse.config.get("initParams") instanceof List);
+
+    queryResponse =
+        new ConfigApi.GetConfigComponent(IndexType.CORE, CORE_NAME, "requestDispatcher")
+            .process(solrTestRule.getSolrClient(CORE_NAME));
+    assertNull(queryResponse.error);
+    assertTrue(queryResponse.config.get("requestDispatcher") instanceof Map);
+
+    queryResponse =
+        new ConfigApi.GetConfigComponent(IndexType.CORE, CORE_NAME, "updateProcessors")
+            .process(solrTestRule.getSolrClient(CORE_NAME));
+    assertNull(queryResponse.error);
+    Map<String, Object> querySection =
+        (Map<String, Object>) queryResponse.config.get("updateProcessors");
+    assertNotNull(querySection);
+    assertTrue(querySection.containsKey("uuid"));
+  }
+
   @Test
   public void testGetConfigComponentByUnknownNameReturnsNotFound() {
     var request =
@@ -255,14 +287,42 @@ public void testGetConfigComponentByUnknownNameReturnsNotFound() {
   }
 
   @Test
-  public void testGetConfigComponentRejectsOldSingularSearchComponentPath() {
-    // v2 intentionally renamed this one section to the plural "searchComponents" in the URL;
+  public void testGetConfigComponentByNameOnListSectionReturnsNotFound() {
+    // List-shaped sections are excluded from the by-name @Path; Jersey should return 404.
+    for (String component :
+        List.of("listeners", "initParams", "updateRequestProcessorChain", "circuitBreaker")) {
+      var request =
+          new ConfigApi.GetConfigComponentByName(IndexType.CORE, CORE_NAME, component, "random");
+      final RemoteSolrException ex =
+          expectThrows(
+              RemoteSolrException.class,
+              () -> request.process(solrTestRule.getSolrClient(CORE_NAME)));
+      assertEquals(404, ex.code());
+    }
+  }
+
+  @Test
+  public void testGetConfigComponentRejectsOldSingularPaths() {
+    // v2-only plurals;
     // the old singular form (still used by v1) shouldn't match the v2 route at all.
-    var request = new ConfigApi.GetConfigComponent(IndexType.CORE, CORE_NAME, "searchComponent");
-    final RemoteSolrException ex =
-        expectThrows(
-            RemoteSolrException.class,
-            () -> request.process(solrTestRule.getSolrClient(CORE_NAME)));
-    assertEquals(404, ex.code());
+    for (String component :
+        List.of(
+            "searchComponent",
+            "queryResponseWriter",
+            "listener",
+            "queryParser",
+            "valueSourceParser",
+            "transformer",
+            "updateProcessor",
+            "queryConverter",
+            "expressible",
+            "cache")) {
+      var request = new ConfigApi.GetConfigComponent(IndexType.CORE, CORE_NAME, component);
+      final RemoteSolrException ex =
+          expectThrows(
+              RemoteSolrException.class,
+              () -> request.process(solrTestRule.getSolrClient(CORE_NAME)));
+      assertEquals(404, ex.code());
+    }
   }
 }
diff --git a/solr/solr-ref-guide/modules/configuration-guide/pages/config-api.adoc b/solr/solr-ref-guide/modules/configuration-guide/pages/config-api.adoc
@@ -124,8 +124,12 @@ The output will be details of each request handler defined in `solrconfig.xml`,
 To see the configuration for implicit request handlers, add `expandParams=true` to the request.
 See the documentation for implicit request handlers linked above for examples using this command.
 
-The available top-level sections that can be added as path parameters are: `query`, `requestHandler`, `searchComponent`, `updateHandler`, `queryResponseWriter`, `initParams`, `znodeVersion`, `listener`, `directoryFactory`, `indexConfig`, and `codecFactory`.
-In the V2 API, `requestHandler`, `searchComponent` and `queryResponseWriter` are exposed under the pluralized names `requestHandlers`, `searchComponents` and `queryResponseWriters` instead (including the response JSON key).
+The available top-level sections that can be added as path parameters include: `query`, `requestHandler`, `searchComponent`, `updateHandler`, `queryResponseWriter`, `initParams`, `znodeVersion`, `listener`, `directoryFactory`, `indexConfig`, and `codecFactory`.
+(Other `solrconfig.xml` sections emitted by Solr may also be fetched the same way)
+
+In the V2 API, several multi-valued sections use pluralized path names (and the same plural as the response JSON key).
+
+V1 paths keep the singular / internal names unchanged.
 
 To further restrict the request to a single component within a top-level section, use the `componentName` request parameter.
 
@@ -166,9 +170,10 @@ The output of this command will look similar to(V1 nests under `requestHandler`;
 }
 ----
 
-The ability to restrict to objects within a top-level section is limited to request handlers (`requestHandler`), search components (`searchComponent`), and response writers (`queryResponseWriter`).
+By-name lookup applies to sections that are maps of named plugins, such as request handlers, search components, response writers etc.
+List-shaped sections like initParams, listeners, updateRequestProcessorChain etc cannot be filtered by name.
 
-For search components and response writers, the V2 API uses a path segment instead of the `componentName` request parameter, under the pluralized section names.
+For those name-keyed sections other than the request handler, the V2 API uses a path segment instead of the `componentName` request parameter, under the pluralized section names.
 For example, to return configuration for the `elevator` search component:
 
 [tabs#getnamedcomponent]
@@ -191,7 +196,7 @@ http://localhost:8983/api/collections/techproducts/config/searchComponents/eleva
 ====
 ======
 
-The same applies to response writers.
+The same pattern applies to other named-key sections.
 For example, to return configuration for the `xslt` response writer:
 
 [tabs#getnamedwriter]
@@ -202,6 +207,7 @@ V1 API::
 [source,bash]
 ----
 http://localhost:8983/solr/techproducts/config/queryResponseWriter?componentName=xslt
+http://localhost:8983/solr/techproducts/config/updateProcessor?componentName=uuid
 ----
 ====
 V2 API::
@@ -210,11 +216,12 @@ V2 API::
 [source,bash]
 ----
 http://localhost:8983/api/collections/techproducts/config/queryResponseWriters/xslt
+http://localhost:8983/api/collections/techproducts/config/updateProcessors/uuid
 ----
 ====
 ======
 
-Request handlers are unaffected and continue to use `componentName` in both APIs, as shown above.
+Request handlers are a special case and continue to use `componentName` in both APIs, as shown above.
 
 == Commands to Modify the Config