Improve null-safety of module/spring-boot-actuator

See gh-46926

module/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/audit/AuditEvent.java

@@ -61,7 +61,7 @@ public class AuditEvent implements Serializable {
 	 * @param type the event type
 	 * @param data the event data
 	 */
-	public AuditEvent(String principal, String type, Map<String, @Nullable Object> data) {
+	public AuditEvent(@Nullable String principal, String type, Map<String, @Nullable Object> data) {
 		this(Instant.now(), principal, type, data);
 	}
 
@@ -72,7 +72,7 @@ public class AuditEvent implements Serializable {
 	 * @param type the event type
 	 * @param data the event data in the form 'key=value' or simply 'key'
 	 */
-	public AuditEvent(String principal, String type, String... data) {
+	public AuditEvent(@Nullable String principal, String type, String... data) {
 		this(Instant.now(), principal, type, convert(data));
 	}
 

module/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/audit/AuditEventsEndpoint.java

@@ -45,8 +45,8 @@ public class AuditEventsEndpoint {
 	}
 
 	@ReadOperation
-	public AuditEventsDescriptor events(@OptionalParameter String principal, @OptionalParameter OffsetDateTime after,
+	public AuditEventsDescriptor events(@OptionalParameter @Nullable String principal,
-			@OptionalParameter String type) {
+			@OptionalParameter @Nullable OffsetDateTime after, @OptionalParameter @Nullable String type) {
 		List<AuditEvent> events = this.auditEventRepository.find(principal, getInstant(after), type);
 		return new AuditEventsDescriptor(events);
 	}

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

@@ -81,12 +81,12 @@ public class EnvironmentEndpoint {
 	}
 
 	@ReadOperation
-	public EnvironmentDescriptor environment(@OptionalParameter String pattern) {
+	public EnvironmentDescriptor environment(@OptionalParameter @Nullable String pattern) {
 		boolean showUnsanitized = this.showValues.isShown(true);
 		return getEnvironmentDescriptor(pattern, showUnsanitized);
 	}
 
-	EnvironmentDescriptor getEnvironmentDescriptor(String pattern, boolean showUnsanitized) {
+	EnvironmentDescriptor getEnvironmentDescriptor(@Nullable String pattern, boolean showUnsanitized) {
 		if (StringUtils.hasText(pattern)) {
 			return getEnvironmentDescriptor(Pattern.compile(pattern).asPredicate(), showUnsanitized);
 		}

module/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/env/EnvironmentEndpointWebExtension.java

@@ -18,6 +18,8 @@ package org.springframework.boot.actuate.env;
 
 import java.util.Set;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.actuate.endpoint.SecurityContext;
 import org.springframework.boot.actuate.endpoint.Show;
 import org.springframework.boot.actuate.endpoint.annotation.OptionalParameter;
@@ -51,7 +53,8 @@ public class EnvironmentEndpointWebExtension {
 	}
 
 	@ReadOperation
-	public EnvironmentDescriptor environment(SecurityContext securityContext, @OptionalParameter String pattern) {
+	public EnvironmentDescriptor environment(SecurityContext securityContext,
+			@OptionalParameter @Nullable String pattern) {
 		boolean showUnsanitized = this.showValues.isShown(securityContext, this.roles);
 		return this.delegate.getEnvironmentDescriptor(pattern, showUnsanitized);
 	}

module/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/logging/LoggersEndpoint.java

@@ -100,7 +100,7 @@ public class LoggersEndpoint {
 	}
 
 	@WriteOperation
-	public void configureLogLevel(@Selector String name, @OptionalParameter LogLevel configuredLevel) {
+	public void configureLogLevel(@Selector String name, @OptionalParameter @Nullable LogLevel configuredLevel) {
 		Assert.notNull(name, "'name' must not be empty");
 		LoggerGroup group = this.loggerGroups.get(name);
 		if (group != null && group.hasMembers()) {

module/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/management/HeapDumpWebEndpoint.java

@@ -78,7 +78,7 @@ public class HeapDumpWebEndpoint {
 	}
 
 	@ReadOperation
-	public WebEndpointResponse<Resource> heapDump(@OptionalParameter Boolean live) {
+	public WebEndpointResponse<Resource> heapDump(@OptionalParameter @Nullable Boolean live) {
 		try {
 			if (this.lock.tryLock(this.timeout, TimeUnit.MILLISECONDS)) {
 				try {
@@ -101,7 +101,7 @@ public class HeapDumpWebEndpoint {
 		return new WebEndpointResponse<>(WebEndpointResponse.STATUS_TOO_MANY_REQUESTS);
 	}
 
-	private Resource dumpHeap(Boolean live) throws IOException, InterruptedException {
+	private Resource dumpHeap(@Nullable Boolean live) throws IOException, InterruptedException {
 		if (this.heapDumper == null) {
 			this.heapDumper = createHeapDumper();
 		}