Fix ordering of JSON property source relative to servlet sources

Fixes gh-17652

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/SpringApplicationJsonEnvironmentPostProcessor.java

@@ -16,10 +16,13 @@
 
 package org.springframework.boot.env;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.json.JsonParser;
@@ -65,6 +68,11 @@ public class SpringApplicationJsonEnvironmentPostProcessor implements Environmen
 	private static final String SERVLET_ENVIRONMENT_CLASS = "org.springframework.web."
 			+ "context.support.StandardServletEnvironment";
 
+	private static final Set<String> SERVLET_ENVIRONMENT_PROPERTY_SOURCES = new LinkedHashSet<>(
+			Arrays.asList(StandardServletEnvironment.JNDI_PROPERTY_SOURCE_NAME,
+					StandardServletEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME,
+					StandardServletEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME));
+
 	/**
 	 * The default order for the processor.
 	 */
@@ -141,10 +149,13 @@ public class SpringApplicationJsonEnvironmentPostProcessor implements Environmen
 	}
 
 	private String findPropertySource(MutablePropertySources sources) {
-		if (ClassUtils.isPresent(SERVLET_ENVIRONMENT_CLASS, null)
-				&& sources.contains(StandardServletEnvironment.JNDI_PROPERTY_SOURCE_NAME)) {
-			return StandardServletEnvironment.JNDI_PROPERTY_SOURCE_NAME;
-
+		if (ClassUtils.isPresent(SERVLET_ENVIRONMENT_CLASS, null)) {
+			PropertySource<?> servletPropertySource = sources.stream()
+					.filter((source) -> SERVLET_ENVIRONMENT_PROPERTY_SOURCES.contains(source.getName())).findFirst()
+					.orElse(null);
+			if (servletPropertySource != null) {
+				return servletPropertySource.getName();
+			}
 		}
 		return StandardEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME;
 	}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/env/SpringApplicationJsonEnvironmentPostProcessorTests.java

@@ -16,14 +16,18 @@
 
 package org.springframework.boot.env;
 
+import java.util.Collections;
+
 import org.junit.Test;
 
 import org.springframework.boot.json.JsonParseException;
 import org.springframework.boot.origin.PropertySourceOrigin;
 import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.PropertySource;
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.test.context.support.TestPropertySourceUtils;
+import org.springframework.web.context.support.StandardServletEnvironment;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@@ -134,4 +138,48 @@ public class SpringApplicationJsonEnvironmentPostProcessorTests {
 		assertThat(this.environment.resolvePlaceholders("${foo:}")).isEqualTo("bar");
 	}
 
+	@Test
+	public void propertySourceShouldBeOrderedBeforeJndiPropertySource() {
+		testServletPropertySource(StandardServletEnvironment.JNDI_PROPERTY_SOURCE_NAME);
+	}
+
+	@Test
+	public void propertySourceShouldBeOrderedBeforeServletContextPropertySource() {
+		testServletPropertySource(StandardServletEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME);
+	}
+
+	@Test
+	public void propertySourceShouldBeOrderedBeforeServletConfigPropertySource() {
+		testServletPropertySource(StandardServletEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME);
+	}
+
+	@Test
+	public void propertySourceOrderingWhenMultipleServletSpecificPropertySources() {
+		MapPropertySource jndi = getPropertySource(StandardServletEnvironment.JNDI_PROPERTY_SOURCE_NAME, "jndi");
+		this.environment.getPropertySources().addFirst(jndi);
+		MapPropertySource servlet = getPropertySource(StandardServletEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME,
+				"servlet");
+		this.environment.getPropertySources().addFirst(servlet);
+		MapPropertySource custom = getPropertySource("custom", "custom");
+		this.environment.getPropertySources().addFirst(custom);
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.environment,
+				"SPRING_APPLICATION_JSON={\"foo\":\"bar\"}");
+		this.processor.postProcessEnvironment(this.environment, null);
+		PropertySource<?> json = this.environment.getPropertySources().get("spring.application.json");
+		assertThat(this.environment.getProperty("foo")).isEqualTo("custom");
+		assertThat(this.environment.getPropertySources()).containsSequence(custom, json, servlet, jndi);
+	}
+
+	private void testServletPropertySource(String servletContextPropertySourceName) {
+		this.environment.getPropertySources().addFirst(getPropertySource(servletContextPropertySourceName, "servlet"));
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.environment,
+				"SPRING_APPLICATION_JSON={\"foo\":\"bar\"}");
+		this.processor.postProcessEnvironment(this.environment, null);
+		assertThat(this.environment.getProperty("foo")).isEqualTo("bar");
+	}
+
+	private MapPropertySource getPropertySource(String name, String value) {
+		return new MapPropertySource(name, Collections.singletonMap("foo", value));
+	}
+
 }