Use JsonMapper instead of ObjectMapper when relevant

This commit updates Jackson 3 JSON support to use JsonMapper
instead of ObjectMapper in converters, codecs and view constructors.

As a consequence, AbstractJacksonDecoder, AbstractJacksonEncoder,
AbstractJacksonHttpMessageConverter and JacksonCodecSupport are
now parameterized with <T extends ObjectMapper>.

Closes gh-35282

spring-test/src/test/java/org/springframework/test/json/AbstractJsonContentAssertTests.java

@@ -45,7 +45,7 @@ import org.junit.jupiter.params.provider.ValueSource;
 import org.skyscreamer.jsonassert.JSONCompareMode;
 import org.skyscreamer.jsonassert.JSONCompareResult;
 import org.skyscreamer.jsonassert.comparator.JSONComparator;
-import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.json.JsonMapper;
 
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.ClassPathResource;
@@ -86,7 +86,7 @@ class AbstractJsonContentAssertTests {
 	private static final String DIFFERENT = loadJson("different.json");
 
 	private static final HttpMessageContentConverter jsonContentConverter = HttpMessageContentConverter.of(
-			new JacksonJsonHttpMessageConverter(new ObjectMapper()));
+			new JacksonJsonHttpMessageConverter(new JsonMapper()));
 
 	private static final JsonComparator comparator = JsonAssert.comparator(JsonCompareMode.LENIENT);
 

spring-test/src/test/java/org/springframework/test/json/JsonPathValueAssertTests.java

@@ -27,7 +27,7 @@ import org.assertj.core.data.Offset;
 import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
-import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.json.JsonMapper;
 
 import org.springframework.http.converter.json.JacksonJsonHttpMessageConverter;
 import org.springframework.test.http.HttpMessageContentConverter;
@@ -206,7 +206,7 @@ class JsonPathValueAssertTests {
 	class ConvertToTests {
 
 		private static final HttpMessageContentConverter jsonContentConverter = HttpMessageContentConverter.of(
-				new JacksonJsonHttpMessageConverter(new ObjectMapper()));
+				new JacksonJsonHttpMessageConverter(new JsonMapper()));
 
 		@Test
 		void convertToWithoutHttpMessageConverter() {

spring-test/src/test/java/org/springframework/test/util/JsonPathExpectationsHelperTests.java

@@ -27,7 +27,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 import tools.jackson.databind.JavaType;
-import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.json.JsonMapper;
 
 import org.springframework.core.ParameterizedTypeReference;
 
@@ -385,14 +385,14 @@ class JsonPathExpectationsHelperTests {
 	 */
 	private static class JacksonMappingProvider implements MappingProvider {
 
-		private final ObjectMapper objectMapper;
+		private final JsonMapper jsonMapper;
 
 		public JacksonMappingProvider() {
-			this(new ObjectMapper());
+			this(new JsonMapper());
 		}
 
-		public JacksonMappingProvider(ObjectMapper objectMapper) {
-			this.objectMapper = objectMapper;
+		public JacksonMappingProvider(JsonMapper jsonMapper) {
+			this.jsonMapper = jsonMapper;
 		}
 
 
@@ -402,7 +402,7 @@ class JsonPathExpectationsHelperTests {
 				return null;
 			}
 			try {
-				return objectMapper.convertValue(source, targetType);
+				return jsonMapper.convertValue(source, targetType);
 			}
 			catch (Exception ex) {
 				throw new MappingException(ex);
@@ -416,10 +416,10 @@ class JsonPathExpectationsHelperTests {
 			if (source == null){
 				return null;
 			}
-			JavaType type = objectMapper.getTypeFactory().constructType(targetType.getType());
+			JavaType type = jsonMapper.getTypeFactory().constructType(targetType.getType());
 
 			try {
-				return (T) objectMapper.convertValue(source, type);
+				return (T) jsonMapper.convertValue(source, type);
 			}
 			catch (Exception ex) {
 				throw new MappingException(ex);

spring-test/src/test/java/org/springframework/test/web/reactive/server/EncoderDecoderMappingProviderTests.java

@@ -22,7 +22,7 @@ import java.util.Map;
 import com.jayway.jsonpath.Configuration;
 import com.jayway.jsonpath.TypeRef;
 import org.junit.jupiter.api.Test;
-import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.json.JsonMapper;
 
 import org.springframework.http.codec.json.JacksonJsonDecoder;
 import org.springframework.http.codec.json.JacksonJsonEncoder;
@@ -36,10 +36,10 @@ import static org.assertj.core.api.Assertions.assertThat;
  */
 class EncoderDecoderMappingProviderTests {
 
-	private static final ObjectMapper objectMapper = new ObjectMapper();
+	private static final JsonMapper jsonMapper = new JsonMapper();
 
 	private final EncoderDecoderMappingProvider mappingProvider = new EncoderDecoderMappingProvider(
-			new JacksonJsonEncoder(objectMapper), new JacksonJsonDecoder(objectMapper));
+			new JacksonJsonEncoder(jsonMapper), new JacksonJsonDecoder(jsonMapper));
 
 
 	@Test

spring-test/src/test/java/org/springframework/test/web/reactive/server/JsonEncoderDecoderTests.java

@@ -19,7 +19,7 @@ package org.springframework.test.web.reactive.server;
 import java.util.List;
 
 import org.junit.jupiter.api.Test;
-import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.json.JsonMapper;
 
 import org.springframework.http.codec.DecoderHttpMessageReader;
 import org.springframework.http.codec.EncoderHttpMessageWriter;
@@ -39,13 +39,13 @@ import static org.assertj.core.api.Assertions.assertThat;
  */
 class JsonEncoderDecoderTests {
 
-	private static final ObjectMapper objectMapper = new ObjectMapper();
+	private static final JsonMapper jsonMapper = new JsonMapper();
 
 	private static final HttpMessageWriter<?> jacksonMessageWriter = new EncoderHttpMessageWriter<>(
-			new JacksonJsonEncoder(objectMapper));
+			new JacksonJsonEncoder(jsonMapper));
 
 	private static final HttpMessageReader<?> jacksonMessageReader = new DecoderHttpMessageReader<>(
-			new JacksonJsonDecoder(objectMapper));
+			new JacksonJsonDecoder(jsonMapper));
 
 	@Test
 	void fromWithEmptyWriters() {