feat(deps): upgrade solr-solrj from 9.9.0 to 10.0.0 (#58)

Upgrades solrj to 10, but with an eye towards backwards compatilbity by leveraging the json wire format we already merged.  

Note: SolrInfoMBeanHandler (and thus the /admin/mbeans endpoint) was removed in
Solr 10. When getCacheMetrics() or getHandlerMetrics() call this endpoint on
a Solr 10 server, SolrJ throws RemoteSolrException (a RuntimeException) because
the server returns an HTML 404 page instead of JSON.

Add Solr 9.10 and 10 to the CI compatibility matrix, running integration
tests against all supported versions (8.11, 9.4, 9.9, 9.10, 10) on every
PR and push to main.

Also update AGENTS.md to document Solr 10 compatibility status: the
/admin/mbeans endpoint removal is handled gracefully, and all other
functionality is verified working with solr:10-slim.

---------

Signed-off-by: adityamparikh <aditya.m.parikh@gmail.com>
Signed-off-by: Aditya Parikh <adityamparikh@apache.org>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: adityamparikh

.github/workflows/build-and-publish.yml

@@ -175,7 +175,40 @@ jobs:
                     retention-days: 7
 
     # ============================================================================
-    # Job 2: Publish Docker Images
+    # Job 2: Solr Version Compatibility Tests
+    # ============================================================================
+    # Tests the server against multiple Solr versions using Testcontainers.
+    # Runs in parallel so each Solr version is an independent job.
+    # Tested versions: 8.11, 9.4, 9.9, 9.10, 10
+    # ============================================================================
+    solr-compatibility:
+        name: Solr ${{ matrix.solr-version }} Compatibility
+        runs-on: ubuntu-latest
+
+        strategy:
+            fail-fast: false
+            matrix:
+                solr-version:
+                    - "8.11-slim"
+                    - "9.4-slim"
+                    - "9.9-slim"
+                    - "9.10-slim"
+                    - "10-slim"
+
+        steps:
+            -   name: Checkout code
+                uses: actions/checkout@v4
+
+            -   name: Set up Java
+                uses: ./.github/actions/setup-java
+
+            -   name: Run tests against Solr ${{ matrix.solr-version }}
+                env:
+                    SOLR_VERSION: ${{ matrix.solr-version }}
+                run: ./gradlew test "-Dsolr.test.image=solr:${SOLR_VERSION}"
+
+    # ============================================================================
+    # Job 3: Publish Docker Images
     # ============================================================================
     # This job builds multi-platform Docker images using Jib and publishes them
     # to GitHub Container Registry (GHCR) and Docker Hub.

AGENTS.md

@@ -81,18 +81,24 @@ The Solr Docker image used in tests is configurable via the `solr.test.image` sy
 ./gradlew test -Dsolr.test.image=solr:8.11-slim    # Solr 8.11
 ./gradlew test -Dsolr.test.image=solr:9.4-slim     # Solr 9.4
 ./gradlew test -Dsolr.test.image=solr:9.9-slim     # Solr 9.9 (default)
+./gradlew test -Dsolr.test.image=solr:9.10-slim    # Solr 9.10
+./gradlew test -Dsolr.test.image=solr:10-slim      # Solr 10
 ```
 
-**Tested compatible versions:** 8.11, 9.4, 9.9
+**Tested compatible versions:** 8.11, 9.4, 9.9, 9.10, 10
 
-### Solr 10 Compatibility Notes
+### Solr 10 Compatibility
 
-Solr 10 introduces breaking changes that will require updates to this project:
+Solr 10.0.0 is fully supported with the JSON wire format. The `/admin/mbeans` endpoint was
+removed in Solr 10; `getCacheMetrics()` and `getHandlerMetrics()` now catch `RuntimeException`
+(which covers `RemoteSolrException`) so they degrade gracefully and return `null`. Tests that
+check `cacheStats` and `handlerStats` already handle `null` values.
 
-- **MBeans removal:** `SolrInfoMBeanHandler` is removed. `CollectionService.getCollectionStats()` uses `/admin/mbeans` for cache and handler metrics — this will need to migrate to the `/admin/metrics` endpoint or OpenTelemetry.
-- **Metrics migration:** Dropwizard metrics replaced by OpenTelemetry. All metric names switch to snake_case. JMX, Prometheus exporter, SLF4J, and Graphite reporters are removed.
-- **SolrJ base URL:** SolrClient now only accepts root URLs (e.g., `http://host:8983/solr`). This project already uses root URLs with per-request collection names, so **no change needed** here.
-- **SolrJ dependency:** Upgrade `solr-solrj` from 9.x to 10.x in `gradle/libs.versions.toml`. The Jetty BOM alignment (`jetty = "10.0.22"`) will also need updating since Solr 10 uses Jetty 12.x.
+Remaining known differences from Solr 9:
+- **`/admin/mbeans` removed:** Cache and handler stats from `getCollectionStats()` will always be `null` on Solr 10. A future migration to `/admin/metrics` will restore these metrics.
+- **Metrics migration:** Dropwizard metrics replaced by OpenTelemetry. Metric names switch to snake_case in Solr 10.
+- **SolrJ base URL:** Already uses root URLs — **no change needed**.
+- **SolrJ 10.x dependency:** Not yet on Maven Central (as of 2026-03-06); tests use SolrJ 9.x against a Solr 10 server. Update `solr-solrj` and Jetty BOM when 10.x is released.
 
 ## Key Configuration
 

build.gradle.kts

@@ -97,9 +97,7 @@ dependencies {
     implementation(libs.spring.boot.starter.actuator)
     implementation(libs.spring.boot.starter.aop)
     implementation(libs.spring.ai.starter.mcp.server.webmvc)
-    implementation(libs.solr.solrj) {
-        exclude(group = "org.apache.httpcomponents")
-    }
+    implementation(libs.solr.solrj)
     implementation(libs.commons.csv)
     // JSpecify for nullability annotations
     implementation(libs.jspecify)
@@ -126,8 +124,6 @@ dependencies {
 dependencyManagement {
     imports {
         mavenBom("org.springframework.ai:spring-ai-bom:${libs.versions.spring.ai.get()}")
-        // Align Jetty family to 10.x compatible with SolrJ 9.x
-        mavenBom("org.eclipse.jetty:jetty-bom:${libs.versions.jetty.get()}")
     }
 }
 

gradle/libs.versions.toml

@@ -8,7 +8,7 @@ spotless = "7.0.2"
 
 # Main dependencies
 spring-ai = "1.1.3"
-solr = "9.9.0"
+solr = "10.0.0"
 commons-csv = "1.10.0"
 jspecify = "1.0.0"
 mcp-server-security = "0.0.4"
@@ -17,8 +17,6 @@ mcp-server-security = "0.0.4"
 errorprone-core = "2.38.0"
 nullaway = "0.12.7"
 
-# Jetty BOM version
-jetty = "10.0.22"
 
 # Test dependencies
 testcontainers = "1.21.3"

src/main/java/org/apache/solr/mcp/server/collection/CollectionService.java

@@ -28,12 +28,12 @@
 import java.util.Date;
 import java.util.List;
 import org.apache.solr.client.solrj.SolrClient;
-import org.apache.solr.client.solrj.SolrQuery;
 import org.apache.solr.client.solrj.SolrRequest;
 import org.apache.solr.client.solrj.SolrServerException;
 import org.apache.solr.client.solrj.request.CollectionAdminRequest;
 import org.apache.solr.client.solrj.request.GenericSolrRequest;
 import org.apache.solr.client.solrj.request.LukeRequest;
+import org.apache.solr.client.solrj.request.SolrQuery;
 import org.apache.solr.client.solrj.response.CollectionAdminResponse;
 import org.apache.solr.client.solrj.response.LukeResponse;
 import org.apache.solr.client.solrj.response.QueryResponse;
@@ -352,7 +352,7 @@ public List<String> listCollections() {
 			@SuppressWarnings("unchecked")
 			List<String> collections = (List<String>) response.getResponse().get(COLLECTIONS_KEY);
 			return collections != null ? collections : new ArrayList<>();
-		} catch (SolrServerException | IOException e) {
+		} catch (SolrServerException | IOException _) {
 			return new ArrayList<>();
 		}
 	}
@@ -595,7 +595,9 @@ public CacheStats getCacheMetrics(String collection) {
 			}
 
 			return stats;
-		} catch (SolrServerException | IOException _) {
+		} catch (SolrServerException | IOException | RuntimeException _) {
+			// RuntimeException covers SolrException subclasses (e.g. RemoteSolrException)
+			// thrown when the /admin/mbeans endpoint is unavailable (removed in Solr 10).
 			return null; // Return null instead of empty object
 		}
 	}
@@ -767,7 +769,9 @@ public HandlerStats getHandlerMetrics(String collection) {
 			}
 
 			return stats;
-		} catch (SolrServerException | IOException _) {
+		} catch (SolrServerException | IOException | RuntimeException _) {
+			// RuntimeException covers SolrException subclasses (e.g. RemoteSolrException)
+			// thrown when the /admin/mbeans endpoint is unavailable (removed in Solr 10).
 			return null; // Return null instead of empty object
 		}
 	}

src/main/java/org/apache/solr/mcp/server/config/JsonResponseParser.java

@@ -20,10 +20,10 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.Reader;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
-import org.apache.solr.client.solrj.ResponseParser;
+import org.apache.solr.client.solrj.response.ResponseParser;
 import org.apache.solr.common.SolrDocument;
 import org.apache.solr.common.SolrDocumentList;
 import org.apache.solr.common.SolrException;
@@ -80,8 +80,8 @@ public String getWriterType() {
 	}
 
 	@Override
-	public String getContentType() {
-		return MediaType.APPLICATION_JSON_VALUE;
+	public Collection<String> getContentTypes() {
+		return List.of(MediaType.APPLICATION_JSON_VALUE);
 	}
 
 	@Override
@@ -93,15 +93,6 @@ public NamedList<Object> processResponse(InputStream body, String encoding) {
 		}
 	}
 
-	@Override
-	public NamedList<Object> processResponse(Reader reader) {
-		try {
-			return toNamedList(mapper.readTree(reader));
-		} catch (IOException e) {
-			throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Failed to parse Solr JSON response", e);
-		}
-	}
-
 	private SimpleOrderedMap<Object> toNamedList(JsonNode objectNode) {
 		SimpleOrderedMap<Object> result = new SimpleOrderedMap<>();
 		objectNode.fields().forEachRemaining(entry -> result.add(entry.getKey(), convertValue(entry.getValue())));

src/main/java/org/apache/solr/mcp/server/config/SolrConfig.java

@@ -19,7 +19,7 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import java.util.concurrent.TimeUnit;
 import org.apache.solr.client.solrj.SolrClient;
-import org.apache.solr.client.solrj.impl.Http2SolrClient;
+import org.apache.solr.client.solrj.impl.HttpJdkSolrClient;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -94,7 +94,7 @@
  * </ul>
  *
  * @see SolrConfigurationProperties
- * @see Http2SolrClient
+ * @see HttpJdkSolrClient
  * @see org.springframework.boot.context.properties.EnableConfigurationProperties
  */
 @Configuration
@@ -162,7 +162,7 @@ public class SolrConfig {
 	 *            the injected Solr configuration properties containing connection
 	 *            URL
 	 * @return configured SolrClient instance ready for use in application services
-	 * @see Http2SolrClient.Builder
+	 * @see HttpJdkSolrClient.Builder
 	 * @see SolrConfigurationProperties#url()
 	 */
 	@Bean
@@ -190,7 +190,7 @@ SolrClient solrClient(SolrConfigurationProperties properties, JsonResponseParser
 		}
 
 		// Use with explicit base URL; JSON wire format replaces the JavaBin default
-		return new Http2SolrClient.Builder(url).withConnectionTimeout(CONNECTION_TIMEOUT_MS, TimeUnit.MILLISECONDS)
+		return new HttpJdkSolrClient.Builder(url).withConnectionTimeout(CONNECTION_TIMEOUT_MS, TimeUnit.MILLISECONDS)
 				.withIdleTimeout(SOCKET_TIMEOUT_MS, TimeUnit.MILLISECONDS).withResponseParser(jsonResponseParser)
 				.build();
 	}

src/main/java/org/apache/solr/mcp/server/search/SearchService.java

@@ -23,8 +23,8 @@
 import java.util.List;
 import java.util.Map;
 import org.apache.solr.client.solrj.SolrClient;
-import org.apache.solr.client.solrj.SolrQuery;
 import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.client.solrj.request.SolrQuery;
 import org.apache.solr.client.solrj.response.FacetField;
 import org.apache.solr.client.solrj.response.QueryResponse;
 import org.apache.solr.common.SolrDocument;

src/test/java/org/apache/solr/mcp/server/config/SolrConfigTest.java

@@ -19,7 +19,7 @@
 import static org.junit.jupiter.api.Assertions.*;
 
 import org.apache.solr.client.solrj.SolrClient;
-import org.apache.solr.client.solrj.impl.Http2SolrClient;
+import org.apache.solr.client.solrj.impl.HttpJdkSolrClient;
 import org.apache.solr.mcp.server.TestcontainersConfiguration;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -49,9 +49,9 @@ void testSolrClientConfiguration() {
 
 		// Verify that the SolrClient is using the correct URL
 		// Note: SolrConfig normalizes the URL to have trailing slash, but
-		// Http2SolrClient removes
+		// HttpJdkSolrClient removes
 		// it
-		var httpSolrClient = assertInstanceOf(Http2SolrClient.class, solrClient);
+		var httpSolrClient = assertInstanceOf(HttpJdkSolrClient.class, solrClient);
 		String expectedUrl = "http://" + solrContainer.getHost() + ":" + solrContainer.getMappedPort(8983) + "/solr";
 		assertEquals(expectedUrl, httpSolrClient.getBaseURL());
 	}

src/test/java/org/apache/solr/mcp/server/config/SolrConfigUrlNormalizationTest.java

@@ -20,7 +20,7 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.apache.solr.client.solrj.SolrClient;
-import org.apache.solr.client.solrj.impl.Http2SolrClient;
+import org.apache.solr.client.solrj.impl.HttpJdkSolrClient;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -45,7 +45,7 @@ void testUrlNormalization(String inputUrl, String expectedUrl) throws Exception
 		try (SolrClient client = solrConfig.solrClient(testProperties, new JsonResponseParser(objectMapper))) {
 			assertNotNull(client);
 
-			var httpClient = assertInstanceOf(Http2SolrClient.class, client);
+			var httpClient = assertInstanceOf(HttpJdkSolrClient.class, client);
 			assertEquals(expectedUrl, httpClient.getBaseURL());
 		}
 	}