Polish "Add Jsonb support"

Closes gh-9648

Author: snicoll

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/GsonHttpMessageConvertersConfiguration.java

@@ -43,7 +43,7 @@ class GsonHttpMessageConvertersConfiguration {
 
 	@Configuration
 	@ConditionalOnBean(Gson.class)
-	@Conditional(PreferGsonOrMissingJacksonAndJsonbCondition.class)
+	@Conditional(PreferGsonOrJacksonAndJsonbUnavailableCondition.class)
 	protected static class GsonHttpMessageConverterConfiguration {
 
 		@Bean
@@ -56,27 +56,28 @@ public GsonHttpMessageConverter gsonHttpMessageConverter(Gson gson) {
 
 	}
 
-	private static class PreferGsonOrMissingJacksonAndJsonbCondition extends AnyNestedCondition {
+	private static class PreferGsonOrJacksonAndJsonbUnavailableCondition
+			extends AnyNestedCondition {
 
-		PreferGsonOrMissingJacksonAndJsonbCondition() {
+		PreferGsonOrJacksonAndJsonbUnavailableCondition() {
 			super(ConfigurationPhase.REGISTER_BEAN);
 		}
 
-		@ConditionalOnProperty(name = HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue = "gson", matchIfMissing = false)
+		@ConditionalOnProperty(name = HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue = "gson")
 		static class GsonPreferred {
 
 		}
 
-		@Conditional(JacksonAndJsonbMissing.class)
-		static class JacksonJsonbMissing {
+		@Conditional(JacksonAndJsonbUnavailable.class)
+		static class JacksonJsonbUnavailable {
 
 		}
 
 	}
 
-	private static class JacksonAndJsonbMissing extends NoneNestedConditions {
+	private static class JacksonAndJsonbUnavailable extends NoneNestedConditions {
 
-		JacksonAndJsonbMissing() {
+		JacksonAndJsonbUnavailable() {
 			super(ConfigurationPhase.REGISTER_BEAN);
 		}
 
@@ -86,7 +87,7 @@ static class JacksonMissing {
 		}
 
 		@ConditionalOnProperty(name = HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue = "jsonb")
-		static class JsonbMissing {
+		static class JsonbPreferred {
 
 		}
 

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/JsonbHttpMessageConvertersConfiguration.java

@@ -23,10 +23,10 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
-import org.springframework.boot.autoconfigure.condition.NoneNestedConditions;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.converter.json.GsonHttpMessageConverter;
 import org.springframework.http.converter.json.JsonbHttpMessageConverter;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 
@@ -55,40 +55,24 @@ public JsonbHttpMessageConverter jsonbHttpMessageConverter(Jsonb jsonb) {
 
 	}
 
-	private static class PreferJsonbOrMissingJacksonAndGsonCondition extends AnyNestedCondition {
+	private static class PreferJsonbOrMissingJacksonAndGsonCondition
+			extends AnyNestedCondition {
 
 		PreferJsonbOrMissingJacksonAndGsonCondition() {
 			super(ConfigurationPhase.REGISTER_BEAN);
 		}
 
-		@ConditionalOnProperty(name = HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue = "jsonb", matchIfMissing = false)
+		@ConditionalOnProperty(name = HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue = "jsonb")
 		static class JsonbPreferred {
 
 		}
 
-		@Conditional(JacksonAndGsonMissing.class)
-		static class JacksonGsonMissing {
+		@ConditionalOnMissingBean({ MappingJackson2HttpMessageConverter.class, GsonHttpMessageConverter.class })
+		static class JacksonAndGsonMissing {
 
 		}
 
 	}
 
-	private static class JacksonAndGsonMissing extends NoneNestedConditions {
-
-		JacksonAndGsonMissing() {
-			super(ConfigurationPhase.REGISTER_BEAN);
-		}
-
-		@ConditionalOnBean(MappingJackson2HttpMessageConverter.class)
-		static class JacksonMissing {
-
-		}
-
-		@ConditionalOnProperty(name = HttpMessageConvertersAutoConfiguration.PREFERRED_MAPPER_PROPERTY, havingValue = "gson")
-		static class GsonMissing {
-
-		}
-
-	}
 
 }

spring-boot-autoconfigure/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -200,7 +200,7 @@
   {
     "name": "spring.http.converters.preferred-json-mapper",
     "type": "java.lang.String",
-    "description": "Preferred JSON mapper to use for HTTP message conversion. Set to \"gson\" to force the use of Gson when both it and Jackson are on the classpath."
+    "description": "Preferred JSON mapper to use for HTTP message conversion, auto-detected according to the environment by default."
   },
   {
     "name": "spring.jersey.type",