Handle wrapper types in Env actuator

This commit modifies the actuator `EnvironmentEndpoint` to allow
primitive wrapper types to be serialized in the response data
structure.

Fixes gh-24307

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/env/EnvironmentEndpoint.java

@@ -44,6 +44,7 @@
 import org.springframework.core.env.PropertySource;
 import org.springframework.core.env.StandardEnvironment;
 import org.springframework.lang.Nullable;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.PropertyPlaceholderHelper;
 import org.springframework.util.StringUtils;
 import org.springframework.util.SystemPropertyUtils;
@@ -184,7 +185,8 @@ public Object sanitize(String name, Object object) {
 	}
 
 	protected Object stringifyIfNecessary(Object value) {
-		if (value == null || value.getClass().isPrimitive()) {
+		if (value == null || ClassUtils.isPrimitiveOrWrapper(value.getClass())
+				|| Number.class.isAssignableFrom(value.getClass())) {
 			return value;
 		}
 		if (CharSequence.class.isAssignableFrom(value.getClass())) {

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/env/EnvironmentEndpointTests.java

@@ -19,6 +19,7 @@
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.math.BigInteger;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -199,7 +200,7 @@ void propertyWithSensitivePlaceholderNotResolved() {
 	}
 
 	@Test
-	void propertyWithTypeOtherThanStringShouldNotFail() {
+	void propertyWithComplexTypeShouldNotFail() {
 		ConfigurableEnvironment environment = emptyEnvironment();
 		environment.getPropertySources()
 				.addFirst(singleKeyPropertySource("test", "foo", Collections.singletonMap("bar", "baz")));
@@ -208,6 +209,23 @@ void propertyWithTypeOtherThanStringShouldNotFail() {
 		assertThat(value).isEqualTo("Complex property type java.util.Collections$SingletonMap");
 	}
 
+	@Test
+	void propertyWithPrimitiveOrWrapperTypeIsHandledCorrectly() {
+		ConfigurableEnvironment environment = emptyEnvironment();
+		Map<String, Object> map = new LinkedHashMap<>();
+		map.put("char", 'a');
+		map.put("integer", 100);
+		map.put("boolean", true);
+		map.put("biginteger", BigInteger.valueOf(200));
+		environment.getPropertySources().addFirst(new MapPropertySource("test", map));
+		EnvironmentDescriptor descriptor = new EnvironmentEndpoint(environment).environment(null);
+		Map<String, PropertyValueDescriptor> properties = propertySources(descriptor).get("test").getProperties();
+		assertThat(properties.get("char").getValue()).isEqualTo('a');
+		assertThat(properties.get("integer").getValue()).isEqualTo(100);
+		assertThat(properties.get("boolean").getValue()).isEqualTo(true);
+		assertThat(properties.get("biginteger").getValue()).isEqualTo(BigInteger.valueOf(200));
+	}
+
 	@Test
 	void propertyWithCharSequenceTypeIsConvertedToString() throws Exception {
 		ConfigurableEnvironment environment = emptyEnvironment();