Merge branch '3.1.x'

Closes gh-38220

spring-boot-project/spring-boot-docker-compose/src/main/java/org/springframework/boot/docker/compose/core/DockerJson.java

@@ -18,6 +18,7 @@
 
 import java.io.IOException;
 import java.util.List;
+import java.util.Locale;
 
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JavaType;
@@ -36,6 +37,7 @@
 final class DockerJson {
 
 	private static final ObjectMapper objectMapper = JsonMapper.builder()
+		.defaultLocale(Locale.ENGLISH)
 		.enable(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES)
 		.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
 		.addModule(new ParameterNamesModule())

spring-boot-project/spring-boot-docker-compose/src/test/java/org/springframework/boot/docker/compose/core/DockerJsonTests.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.docker.compose.core;
 
 import java.util.List;
+import java.util.Locale;
 
 import org.junit.jupiter.api.Test;
 
@@ -68,7 +69,33 @@ void deserializeToListWhenMultipleLines() {
 		assertThat(response).containsExactly(new TestResponse(1), new TestResponse(2));
 	}
 
+	@Test
+	void shouldBeLocaleAgnostic() {
+		// Turkish locale lower cases the 'I' to a 'ı', not to an 'i'
+		withLocale(Locale.forLanguageTag("tr-TR"), () -> {
+			String json = """
+					{ "INTEGER": 42 }
+					""";
+			TestLowercaseResponse response = DockerJson.deserialize(json, TestLowercaseResponse.class);
+			assertThat(response.integer()).isEqualTo(42);
+		});
+	}
+
+	private void withLocale(Locale locale, Runnable runnable) {
+		Locale defaultLocale = Locale.getDefault();
+		try {
+			Locale.setDefault(locale);
+			runnable.run();
+		}
+		finally {
+			Locale.setDefault(defaultLocale);
+		}
+	}
+
 	record TestResponse(int value) {
 	}
 
+	record TestLowercaseResponse(int integer) {
+	}
+
 }