Migrate to Spring JCL logging.

Original Pull Request #2001
Closes #2000

pom.xml

@@ -147,21 +147,6 @@
 			</exclusions>
 		</dependency>
 
-		<!-- Logging -->
-		<dependency>
-			<groupId>org.slf4j</groupId>
-			<artifactId>log4j-over-slf4j</artifactId>
-			<version>${slf4j}</version>
-			<scope>test</scope>
-		</dependency>
-
-		<dependency>
-			<groupId>org.apache.logging.log4j</groupId>
-			<artifactId>log4j-core</artifactId>
-			<version>${log4j}</version>
-			<scope>test</scope>
-		</dependency>
-
 		<!-- Jackson JSON Mapper -->
 		<dependency>
 			<groupId>com.fasterxml.jackson.core</groupId>
@@ -223,13 +208,6 @@
 			</exclusions>
 		</dependency>
 
-		<dependency>
-			<groupId>org.apache.logging.log4j</groupId>
-			<artifactId>log4j-to-slf4j</artifactId>
-			<version>${log4j}</version>
-			<scope>test</scope>
-		</dependency>
-
 		<dependency>
 			<groupId>io.projectreactor.tools</groupId>
 			<artifactId>blockhound-junit-platform</artifactId>

src/main/java/org/springframework/data/elasticsearch/backend/elasticsearch7/ElasticsearchRestTemplate.java

@@ -24,6 +24,8 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.Version;
 import org.elasticsearch.action.DocWriteResponse;
 import org.elasticsearch.action.bulk.BulkItemResponse;
@@ -54,8 +56,6 @@
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
 import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 import org.elasticsearch.search.suggest.SuggestBuilder;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.data.elasticsearch.BulkFailureException;
 import org.springframework.data.elasticsearch.backend.elasticsearch7.cluster.ElasticsearchClusterOperations;
 import org.springframework.data.elasticsearch.backend.elasticsearch7.document.DocumentAdapters;
@@ -116,7 +116,7 @@
  */
 public class ElasticsearchRestTemplate extends AbstractElasticsearchTemplate {
 
-	private static final Logger LOGGER = LoggerFactory.getLogger(ElasticsearchRestTemplate.class);
+	private static final Log LOGGER = LogFactory.getLog(ElasticsearchRestTemplate.class);
 
 	private final RestHighLevelClient client;
 	private final ElasticsearchExceptionTranslator exceptionTranslator = new ElasticsearchExceptionTranslator();
@@ -419,7 +419,7 @@ public void searchScrollClear(List<String> scrollIds) {
 			request.scrollIds(scrollIds);
 			execute(client -> client.clearScroll(request, RequestOptions.DEFAULT));
 		} catch (Exception e) {
-			LOGGER.warn("Could not clear scroll: {}", e.getMessage());
+			LOGGER.warn(String.format("Could not clear scroll: %s", e.getMessage()));
 		}
 	}
 

src/main/java/org/springframework/data/elasticsearch/backend/elasticsearch7/ReactiveElasticsearchTemplate.java

@@ -26,6 +26,8 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.Version;
 import org.elasticsearch.action.DocWriteResponse;
 import org.elasticsearch.action.bulk.BulkItemResponse;
@@ -47,8 +49,6 @@
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
 import org.elasticsearch.search.suggest.SuggestBuilder;
 import org.reactivestreams.Publisher;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
@@ -109,8 +109,7 @@
  */
 public class ReactiveElasticsearchTemplate implements ReactiveElasticsearchOperations, ApplicationContextAware {
 
-	private static final Logger QUERY_LOGGER = LoggerFactory
-			.getLogger("org.springframework.data.elasticsearch.core.QUERY");
+	private static final Log QUERY_LOGGER = LogFactory.getLog("org.springframework.data.elasticsearch.core.QUERY");
 
 	private final ReactiveElasticsearchClient client;
 	private final ElasticsearchConverter converter;
@@ -811,7 +810,7 @@ public Flux<AggregationContainer<?>> aggregate(Query query, Class<?> entityType,
 	protected Flux<AggregationContainer<?>> doAggregate(SearchRequest request) {
 
 		if (QUERY_LOGGER.isDebugEnabled()) {
-			QUERY_LOGGER.debug("Executing doCount: {}", request);
+			QUERY_LOGGER.debug(String.format("Executing doCount: %s", request));
 		}
 
 		return Flux.from(execute(client -> client.aggregate(request))) //
@@ -885,7 +884,7 @@ private Mono<Long> doCount(Query query, Class<?> entityType, IndexCoordinates in
 	protected Flux<SearchDocument> doFind(SearchRequest request) {
 
 		if (QUERY_LOGGER.isDebugEnabled()) {
-			QUERY_LOGGER.debug("Executing doFind: {}", request);
+			QUERY_LOGGER.debug(String.format("Executing doFind: %s", request));
 		}
 
 		return Flux.from(execute(client -> client.search(request))).map(DocumentAdapters::from) //
@@ -903,7 +902,7 @@ protected Mono<SearchDocumentResponse> doFindForResponse(SearchRequest request,
 			Function<SearchDocument, ? extends Object> suggestEntityCreator) {
 
 		if (QUERY_LOGGER.isDebugEnabled()) {
-			QUERY_LOGGER.debug("Executing doFindForResponse: {}", request);
+			QUERY_LOGGER.debug(String.format("Executing doFindForResponse: %s", request));
 		}
 
 		return Mono.from(execute(client1 -> client1.searchForResponse(request))).map(searchResponse -> {
@@ -920,7 +919,7 @@ protected Mono<SearchDocumentResponse> doFindForResponse(SearchRequest request,
 	protected Mono<Long> doCount(SearchRequest request) {
 
 		if (QUERY_LOGGER.isDebugEnabled()) {
-			QUERY_LOGGER.debug("Executing doCount: {}", request);
+			QUERY_LOGGER.debug(String.format("Executing doCount: %s", request));
 		}
 
 		return Mono.from(execute(client -> client.count(request))) //
@@ -936,7 +935,7 @@ protected Mono<Long> doCount(SearchRequest request) {
 	protected Flux<SearchDocument> doScroll(SearchRequest request) {
 
 		if (QUERY_LOGGER.isDebugEnabled()) {
-			QUERY_LOGGER.debug("Executing doScroll: {}", request);
+			QUERY_LOGGER.debug(String.format("Executing doScroll: %s", request));
 		}
 
 		return Flux.from(execute(client -> client.scroll(request))) //

src/main/java/org/springframework/data/elasticsearch/backend/elasticsearch7/ReactiveIndexTemplate.java

@@ -24,6 +24,8 @@
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.elasticsearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
@@ -36,8 +38,6 @@
 import org.elasticsearch.client.indices.GetMappingsRequest;
 import org.elasticsearch.client.indices.IndexTemplatesExistRequest;
 import org.elasticsearch.client.indices.PutIndexTemplateRequest;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.data.elasticsearch.NoSuchIndexException;
@@ -69,7 +69,7 @@
  */
 class ReactiveIndexTemplate implements ReactiveIndexOperations {
 
-	private static final Logger LOGGER = LoggerFactory.getLogger(ReactiveIndexTemplate.class);
+	private static final Log LOGGER = LogFactory.getLog(ReactiveIndexTemplate.class);
 
 	@Nullable private final Class<?> boundClass;
 	private final IndexCoordinates boundIndex;
@@ -366,7 +366,7 @@ private Mono<Document> loadDocument(String path, String annotation) {
 				}
 			});
 		} else {
-			LOGGER.info("path in {} has to be defined. Using default instead.", annotation);
+			LOGGER.info(String.format("path in %s has to be defined. Using default empty Document instead.", annotation));
 		}
 
 		return Mono.just(Document.create());

src/main/java/org/springframework/data/elasticsearch/backend/elasticsearch7/RestIndexTemplate.java

@@ -20,6 +20,8 @@
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.elasticsearch.action.admin.indices.alias.IndicesAliasesRequest;
 import org.elasticsearch.action.admin.indices.alias.get.GetAliasesRequest;
 import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
@@ -38,8 +40,6 @@
 import org.elasticsearch.client.indices.PutIndexTemplateRequest;
 import org.elasticsearch.client.indices.PutMappingRequest;
 import org.elasticsearch.cluster.metadata.MappingMetadata;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.data.elasticsearch.core.AbstractIndexTemplate;
 import org.springframework.data.elasticsearch.core.IndexInformation;
 import org.springframework.data.elasticsearch.core.IndexOperations;
@@ -66,7 +66,7 @@
  */
 class RestIndexTemplate extends AbstractIndexTemplate implements IndexOperations {
 
-	private static final Logger LOGGER = LoggerFactory.getLogger(RestIndexTemplate.class);
+	private static final Log LOGGER = LogFactory.getLog(RestIndexTemplate.class);
 
 	private final ElasticsearchRestTemplate restTemplate;
 

src/main/java/org/springframework/data/elasticsearch/backend/elasticsearch7/client/RestClientFactoryBean.java

@@ -18,11 +18,11 @@
 import java.net.URL;
 import java.util.ArrayList;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.http.HttpHost;
 import org.elasticsearch.client.RestClient;
 import org.elasticsearch.client.RestHighLevelClient;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.FactoryBeanNotInitializedException;
@@ -38,7 +38,7 @@
  */
 public class RestClientFactoryBean implements FactoryBean<RestHighLevelClient>, InitializingBean, DisposableBean {
 
-	private static final Logger LOGGER = LoggerFactory.getLogger(RestClientFactoryBean.class);
+	private static final Log LOGGER = LogFactory.getLog(RestClientFactoryBean.class);
 
 	private @Nullable RestHighLevelClient client;
 	private String hosts = "http://localhost:9200";

src/main/java/org/springframework/data/elasticsearch/client/ClientLogger.java

@@ -17,16 +17,15 @@
 
 import java.util.function.Supplier;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.http.HttpStatus;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;
 
 /**
  * Logging Utility to log client requests and responses. Logs client requests and responses to Elasticsearch to a
- * dedicated logger: {@code org.springframework.data.elasticsearch.client.WIRE} on {@link org.slf4j.event.Level#TRACE}
- * level.
+ * dedicated logger: {@code org.springframework.data.elasticsearch.client.WIRE} on trace level.
  *
  * @author Mark Paluch
  * @author Christoph Strobl
@@ -35,8 +34,7 @@
 public abstract class ClientLogger {
 
 	private static final String lineSeparator = System.getProperty("line.separator");
-	private static final Logger WIRE_LOGGER = LoggerFactory
-			.getLogger("org.springframework.data.elasticsearch.client.WIRE");
+	private static final Log WIRE_LOGGER = LogFactory.getLog("org.springframework.data.elasticsearch.client.WIRE");
 
 	private ClientLogger() {}
 
@@ -52,24 +50,23 @@ public static boolean isEnabled() {
 	/**
 	 * Log an outgoing HTTP request.
 	 *
-	 * @param logId the correlation Id, see {@link #newLogId()}.
+	 * @param logId the correlation id, see {@link #newLogId()}.
 	 * @param method HTTP method
 	 * @param endpoint URI
 	 * @param parameters optional parameters.
 	 */
 	public static void logRequest(String logId, String method, String endpoint, Object parameters) {
 
 		if (isEnabled()) {
-
-			WIRE_LOGGER.trace("[{}] Sending request {} {} with parameters: {}", logId, method.toUpperCase(), endpoint,
-					parameters);
+			WIRE_LOGGER.trace(String.format("[%s] Sending request %s %s with parameters: %s", logId, method.toUpperCase(),
+					endpoint, parameters));
 		}
 	}
 
 	/**
 	 * Log an outgoing HTTP request with a request body.
 	 *
-	 * @param logId the correlation Id, see {@link #newLogId()}.
+	 * @param logId the correlation id, see {@link #newLogId()}.
 	 * @param method HTTP method
 	 * @param endpoint URI
 	 * @param parameters optional parameters.
@@ -79,43 +76,43 @@ public static void logRequest(String logId, String method, String endpoint, Obje
 			Supplier<Object> body) {
 
 		if (isEnabled()) {
-
-			WIRE_LOGGER.trace("[{}] Sending request {} {} with parameters: {}{}Request body: {}", logId, method.toUpperCase(),
-					endpoint, parameters, lineSeparator, body.get());
+			WIRE_LOGGER.trace(String.format("[%s] Sending request %s %s with parameters: %s%sRequest body: %s", logId,
+					method.toUpperCase(), endpoint, parameters, lineSeparator, body.get()));
 		}
 	}
 
 	/**
 	 * Log a raw HTTP response without logging the body.
 	 *
-	 * @param logId the correlation Id, see {@link #newLogId()}.
+	 * @param logId the correlation id, see {@link #newLogId()}.
 	 * @param statusCode the HTTP status code.
 	 */
 	public static void logRawResponse(String logId, @Nullable HttpStatus statusCode) {
 
 		if (isEnabled()) {
-			WIRE_LOGGER.trace("[{}] Received raw response: {}", logId, statusCode);
+			WIRE_LOGGER.trace(String.format("[%s] Received raw response: %s", logId, statusCode));
 		}
 	}
 
 	/**
 	 * Log a raw HTTP response along with the body.
 	 *
-	 * @param logId the correlation Id, see {@link #newLogId()}.
+	 * @param logId the correlation id, see {@link #newLogId()}.
 	 * @param statusCode the HTTP status code.
 	 * @param body body content.
 	 */
 	public static void logResponse(String logId, HttpStatus statusCode, String body) {
 
 		if (isEnabled()) {
-			WIRE_LOGGER.trace("[{}] Received response: {}{}Response body: {}", logId, statusCode, lineSeparator, body);
+			WIRE_LOGGER.trace(
+					String.format("[%s] Received response: %s%sResponse body: %s", logId, statusCode, lineSeparator, body));
 		}
 	}
 
 	/**
-	 * Creates a new, unique correlation Id to improve tracing across log events.
+	 * Creates a new, unique correlation id to improve tracing across log events.
 	 *
-	 * @return a new, unique correlation Id.
+	 * @return a new, unique correlation id.
 	 */
 	public static String newLogId() {