Fix JVM <clinit> deadlock by removing static final accessor fields (#48689)

* Fix JVM <clinit> deadlock and CosmosItemSerializer.DEFAULT_SERIALIZER null

Fixes #48622, #48585

Replace all static final accessor fields and inline
ImplementationBridgeHelpers calls with uniform private static getter
methods. This eliminates <clinit>-time class loading that caused
permanent deadlocks under concurrent class initialization (JLS 12.4.2).

Fix CosmosItemSerializer.DEFAULT_SERIALIZER circular <clinit> —
create instance directly and move INTERNAL_DEFAULT_SERIALIZER to
parent class to prevent concurrent <clinit> between parent and child.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix review comments: remove duplicate imports, add getter pattern

- ModelBridgeInternal.java: Remove 26 duplicate ImplementationBridgeHelpers imports
- ItemBulkOperation.java: Remove 2 duplicate ImplementationBridgeHelpers imports
- SqlQuerySpecWithEncryption.java: Add private static internalDefaultSerializer()
  getter (matching uniform pattern), replace inline accessor calls, remove
  unused DefaultCosmosItemSerializer import

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix misleading JavaDoc on allAccessorClassesMustHaveStaticInitializerBlock test

Clarify that the test verifies accessor resolvability (via <clinit> or
initializeAllAccessors fallback), not that each class independently
registers its accessor. Structural enforcement is done by the companion
noStaticOrInstanceAccessorFieldsInConsumingClasses test.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Refactoring.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jeet1995

sdk/cosmos/azure-cosmos-encryption/src/main/java/com/azure/cosmos/encryption/models/SqlQuerySpecWithEncryption.java

@@ -7,11 +7,11 @@
 import com.azure.cosmos.encryption.CosmosEncryptionAsyncContainer;
 import com.azure.cosmos.encryption.implementation.Constants;
 import com.azure.cosmos.encryption.implementation.EncryptionImplementationBridgeHelpers;
+import com.azure.cosmos.implementation.ImplementationBridgeHelpers;
 import com.azure.cosmos.encryption.implementation.EncryptionProcessor;
 import com.azure.cosmos.encryption.implementation.EncryptionUtils;
 import com.azure.cosmos.encryption.implementation.mdesrc.cryptography.EncryptionType;
 import com.azure.cosmos.encryption.implementation.mdesrc.cryptography.MicrosoftDataEncryptionException;
-import com.azure.cosmos.implementation.DefaultCosmosItemSerializer;
 import com.azure.cosmos.implementation.Utils;
 import com.azure.cosmos.implementation.apachecommons.lang.StringUtils;
 import com.azure.cosmos.implementation.apachecommons.lang.tuple.Pair;
@@ -33,6 +33,11 @@ public final class SqlQuerySpecWithEncryption {
     private final HashMap<String, SqlParameter> encryptionParamMap = new HashMap<>();
     private final EncryptionImplementationBridgeHelpers.CosmosEncryptionAsyncContainerHelper.CosmosEncryptionAsyncContainerAccessor cosmosEncryptionAsyncContainerAccessor = EncryptionImplementationBridgeHelpers.CosmosEncryptionAsyncContainerHelper.getCosmosEncryptionAsyncContainerAccessor();
 
+    private static CosmosItemSerializer internalDefaultSerializer() {
+        return ImplementationBridgeHelpers.CosmosItemSerializerHelper
+            .getCosmosItemSerializerAccessor().getInternalDefaultSerializer();
+    }
+
     /**
      * Creates a new instance of SQL query spec with encryption.
      *
@@ -86,10 +91,10 @@ Mono<Void> addEncryptionParameterAsync(String path, SqlParameter sqlParameter,
                                 }
                                 byte[] valueByte =
                                     EncryptionUtils.serializeJsonToByteArray(
-                                        DefaultCosmosItemSerializer.INTERNAL_DEFAULT_SERIALIZER,
+                                        internalDefaultSerializer(),
                                         sqlParameter.getValue(Object.class));
                                 JsonNode itemJObj = Utils.parse(
-                                    valueByte, JsonNode.class, DefaultCosmosItemSerializer.INTERNAL_DEFAULT_SERIALIZER);
+                                    valueByte, JsonNode.class, internalDefaultSerializer());
                                 Pair<EncryptionProcessor.TypeMarker, byte[]> typeMarkerPair =
                                     EncryptionProcessor.toByteArray(itemJObj);
                                 byte[] cipherText =

sdk/cosmos/azure-cosmos-tests/src/test/java/com/azure/cosmos/implementation/ImplementationBridgeHelpersTest.java

@@ -8,6 +8,7 @@
 
 #### Bugs Fixed
 * Fixed an issue where change feed with `startFrom` point-in-time returned `400` on merged partitions by enabling the `CHANGE_FEED_WITH_START_TIME_POST_MERGE` SDK capability.
+* Fixed JVM `<clinit>` deadlock when multiple threads concurrently trigger Cosmos SDK class loading for the first time. - See [PR 48689](https://github.com/Azure/azure-sdk-for-java/pull/48689)
 
 #### Other Changes
 

sdk/cosmos/azure-cosmos/CHANGELOG.md

@@ -79,22 +79,25 @@
     builder = CosmosClientBuilder.class,
     isAsync = true)
 public final class CosmosAsyncClient implements Closeable {
+    private static ImplementationBridgeHelpers.CosmosClientTelemetryConfigHelper.CosmosClientTelemetryConfigAccessor clientTelemetryConfigAccessor() {
+        return ImplementationBridgeHelpers.CosmosClientTelemetryConfigHelper.getCosmosClientTelemetryConfigAccessor();
+    }
+
+    private static ImplementationBridgeHelpers.ReadConsistencyStrategyHelper.ReadConsistencyStrategyAccessor readConsistencyStrategyAccessor() {
+        return ImplementationBridgeHelpers.ReadConsistencyStrategyHelper.getReadConsistencyStrategyAccessor();
+    }
+
+    private static ImplementationBridgeHelpers.CosmosQueryRequestOptionsHelper.CosmosQueryRequestOptionsAccessor queryOptionsAccessor() {
+        return ImplementationBridgeHelpers.CosmosQueryRequestOptionsHelper.getCosmosQueryRequestOptionsAccessor();
+    }
+
+    private static ImplementationBridgeHelpers.FeedResponseHelper.FeedResponseAccessor feedResponseAccessor() {
+        return ImplementationBridgeHelpers.FeedResponseHelper.getFeedResponseAccessor();
+    }
+
     private static final Logger logger = LoggerFactory.getLogger(CosmosAsyncClient.class);
 
     private static final CosmosClientTelemetryConfig DEFAULT_TELEMETRY_CONFIG = new CosmosClientTelemetryConfig();
-    private static final ImplementationBridgeHelpers.CosmosQueryRequestOptionsHelper.CosmosQueryRequestOptionsAccessor queryOptionsAccessor =
-        ImplementationBridgeHelpers.CosmosQueryRequestOptionsHelper.getCosmosQueryRequestOptionsAccessor();
-    private static final ImplementationBridgeHelpers.FeedResponseHelper.FeedResponseAccessor feedResponseAccessor =
-        ImplementationBridgeHelpers.FeedResponseHelper.getFeedResponseAccessor();
-    private static final ImplementationBridgeHelpers.CosmosClientTelemetryConfigHelper.CosmosClientTelemetryConfigAccessor
-        telemetryConfigAccessor = ImplementationBridgeHelpers
-        .CosmosClientTelemetryConfigHelper
-        .getCosmosClientTelemetryConfigAccessor();
-
-    private static final ImplementationBridgeHelpers.ReadConsistencyStrategyHelper.ReadConsistencyStrategyAccessor
-        readConsistencyStrategyAccessor = ImplementationBridgeHelpers
-            .ReadConsistencyStrategyHelper
-            .getReadConsistencyStrategyAccessor();
 
     private final static Function<CosmosAsyncContainer, CosmosAsyncContainer> DEFAULT_CONTAINER_FACTORY =
         (originalContainer) -> originalContainer;
@@ -148,7 +151,7 @@ public final class CosmosAsyncClient implements Closeable {
         this.clientTelemetryConfig = effectiveTelemetryConfig;
         boolean contentResponseOnWriteEnabled = builder.isContentResponseOnWriteEnabled();
         ApiType apiType = builder.apiType();
-        String clientCorrelationId = telemetryConfigAccessor
+        String clientCorrelationId = clientTelemetryConfigAccessor()
             .getClientCorrelationId(effectiveTelemetryConfig);
 
         List<Permission> permissionList = new ArrayList<>();
@@ -207,15 +210,14 @@ public final class CosmosAsyncClient implements Closeable {
             TagName.ClientCorrelationId.toString(),
             ClientTelemetryMetrics.escape(effectiveClientCorrelationId));
 
-        this.clientMetricRegistrySnapshot = telemetryConfigAccessor
+        this.clientMetricRegistrySnapshot = clientTelemetryConfigAccessor()
             .getClientMetricRegistry(effectiveTelemetryConfig);
 
-        CosmosMeterOptions cpuMeterOptions = telemetryConfigAccessor
+        CosmosMeterOptions cpuMeterOptions = clientTelemetryConfigAccessor()
             .getMeterOptions(effectiveTelemetryConfig, CosmosMetricName.SYSTEM_CPU);
-        CosmosMeterOptions memoryMeterOptions = telemetryConfigAccessor
+        CosmosMeterOptions memoryMeterOptions = clientTelemetryConfigAccessor()
             .getMeterOptions(effectiveTelemetryConfig, CosmosMetricName.SYSTEM_MEMORY_FREE);
 
-
         if (clientMetricRegistrySnapshot != null) {
             ClientTelemetryMetrics.add(clientMetricRegistrySnapshot, cpuMeterOptions, memoryMeterOptions);
         }
@@ -224,15 +226,15 @@ public final class CosmosAsyncClient implements Closeable {
         );
 
         if (this.clientMetricRegistrySnapshot != null) {
-            telemetryConfigAccessor.setClientCorrelationTag(
+            clientTelemetryConfigAccessor().setClientCorrelationTag(
                 effectiveTelemetryConfig,
                 this.clientCorrelationTag );
-            telemetryConfigAccessor.setAccountName(
+            clientTelemetryConfigAccessor().setAccountName(
                 effectiveTelemetryConfig,
                 this.accountTagValue
             );
 
-            telemetryConfigAccessor.addDiagnosticsHandler(
+            clientTelemetryConfigAccessor().addDiagnosticsHandler(
                 effectiveTelemetryConfig,
                 new ClientMetricsDiagnosticsHandler(this)
             );
@@ -475,7 +477,7 @@ CosmosPagedFlux<CosmosDatabaseProperties> readAllDatabases(CosmosQueryRequestOpt
                 null,
                 ResourceType.Database,
                 OperationType.ReadFeed,
-                queryOptionsAccessor.getQueryNameOrDefault(nonNullOptions, spanName),
+                queryOptionsAccessor().getQueryNameOrDefault(nonNullOptions, spanName),
                 nonNullOptions,
                 pagedFluxOptions
             );
@@ -484,7 +486,7 @@ CosmosPagedFlux<CosmosDatabaseProperties> readAllDatabases(CosmosQueryRequestOpt
 
             return getDocClientWrapper().readDatabases(state)
                 .map(response ->
-                    feedResponseAccessor.createFeedResponse(
+                    feedResponseAccessor().createFeedResponse(
                         ModelBridgeInternal.getCosmosDatabasePropertiesFromV2Results(response.getResults()),
                         response.getResponseHeaders(),
                         response.getCosmosDiagnostics()));
@@ -504,7 +506,6 @@ public CosmosPagedFlux<CosmosDatabaseProperties> readAllDatabases() {
         return readAllDatabases(new CosmosQueryRequestOptions());
     }
 
-
     /**
      * Query for databases.
      * <br/>
@@ -662,22 +663,21 @@ private CosmosPagedFlux<CosmosDatabaseProperties> queryDatabasesInternal(
                 null,
                 ResourceType.Database,
                 OperationType.Query,
-                queryOptionsAccessor.getQueryNameOrDefault(nonNullOptions, spanName),
+                queryOptionsAccessor().getQueryNameOrDefault(nonNullOptions, spanName),
                 nonNullOptions,
                 pagedFluxOptions
             );
 
             pagedFluxOptions.setFeedOperationState(state);
 
             return getDocClientWrapper().queryDatabases(querySpec, state)
-                .map(response -> feedResponseAccessor.createFeedResponse(
+                .map(response -> feedResponseAccessor().createFeedResponse(
                     ModelBridgeInternal.getCosmosDatabasePropertiesFromV2Results(response.getResults()),
                     response.getResponseHeaders(),
                     response.getCosmosDiagnostics()));
         });
     }
 
-
     private Mono<CosmosDatabaseResponse> createDatabaseIfNotExistsInternal(CosmosAsyncDatabase database,
                                                                            ThroughputProperties throughputProperties, Context context) {
         String spanName = "createDatabaseIfNotExists." + database.getId();
@@ -765,7 +765,7 @@ ReadConsistencyStrategy getEffectiveReadConsistencyStrategy(
         OperationType operationType,
         ReadConsistencyStrategy desiredReadConsistencyStrategyOfOperation) {
 
-        return readConsistencyStrategyAccessor.getEffectiveReadConsistencyStrategy(
+        return readConsistencyStrategyAccessor().getEffectiveReadConsistencyStrategy(
             resourceType,
             operationType,
             desiredReadConsistencyStrategyOfOperation,
@@ -780,13 +780,12 @@ CosmosDiagnosticsThresholds getEffectiveDiagnosticsThresholds(
             return operationLevelThresholds;
         }
 
-
         if (this.clientTelemetryConfig == null) {
             return new CosmosDiagnosticsThresholds();
         }
 
         CosmosDiagnosticsThresholds clientLevelThresholds =
-            telemetryConfigAccessor.getDiagnosticsThresholds(this.clientTelemetryConfig);
+            clientTelemetryConfigAccessor().getDiagnosticsThresholds(this.clientTelemetryConfig);
 
         return clientLevelThresholds != null ? clientLevelThresholds : new CosmosDiagnosticsThresholds();
     }
@@ -805,15 +804,15 @@ boolean isTransportLevelTracingEnabled() {
             this.clientTelemetryConfig
             : DEFAULT_TELEMETRY_CONFIG;
 
-        if (telemetryConfigAccessor.isLegacyTracingEnabled(effectiveConfig)) {
+        if (clientTelemetryConfigAccessor().isLegacyTracingEnabled(effectiveConfig)) {
             return false;
         }
 
         if (this.getConnectionPolicy().getConnectionMode() != ConnectionMode.DIRECT) {
             return false;
         }
 
-        return telemetryConfigAccessor.isTransportLevelTracingEnabled(effectiveConfig);
+        return clientTelemetryConfigAccessor().isTransportLevelTracingEnabled(effectiveConfig);
     }
 
     void recordOpenConnectionsAndInitCachesCompleted(List<CosmosContainerIdentity> cosmosContainerIdentities) {
@@ -859,13 +858,13 @@ public String getAccountTagValue(CosmosAsyncClient client) {
 
                 @Override
                 public EnumSet<TagName> getMetricTagNames(CosmosAsyncClient client) {
-                    return  telemetryConfigAccessor
+                    return  clientTelemetryConfigAccessor()
                         .getMetricTagNames(client.clientTelemetryConfig);
                 }
 
                 @Override
                 public EnumSet<MetricCategory> getMetricCategories(CosmosAsyncClient client) {
-                    return  telemetryConfigAccessor
+                    return  clientTelemetryConfigAccessor()
                         .getMetricCategories(client.clientTelemetryConfig);
                 }
 
@@ -896,7 +895,7 @@ public String getUserAgent(CosmosAsyncClient client) {
 
                 @Override
                 public CosmosMeterOptions getMeterOptions(CosmosAsyncClient client, CosmosMetricName name) {
-                    return  telemetryConfigAccessor
+                    return  clientTelemetryConfigAccessor()
                         .getMeterOptions(client.clientTelemetryConfig, name);
                 }