From 51ec3ce3dfb047a5e5bb774b801668912dbb0e01 Mon Sep 17 00:00:00 2001
From: Moritz Halbritter <moritz.halbritter@broadcom.com>
Date: Fri, 1 Aug 2025 14:57:10 +0200
Subject: [PATCH] Add nullability annotations to module/spring-boot-liquibase

See gh-46587
---
 ...uibaseChangelogMissingFailureAnalyzer.java |  12 +-
 .../LiquibaseAutoConfiguration.java           |  19 ++--
 .../LiquibaseConnectionDetails.java           |  10 +-
 .../autoconfigure/LiquibaseProperties.java    | 103 +++++++++---------
 .../autoconfigure/endpoint/package-info.java  |   3 +
 .../liquibase/autoconfigure/package-info.java |   3 +
 ...tingLiquibaseConnectionDetailsFactory.java |   6 +-
 .../docker/compose/package-info.java          |   3 +
 .../liquibase/endpoint/LiquibaseEndpoint.java |  12 +-
 .../boot/liquibase/endpoint/package-info.java |   3 +
 .../boot/liquibase/package-info.java          |   3 +
 .../testcontainers/package-info.java          |   3 +
 12 files changed, 104 insertions(+), 76 deletions(-)

diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/LiquibaseChangelogMissingFailureAnalyzer.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/LiquibaseChangelogMissingFailureAnalyzer.java
index 3367b0b054e..afc867b34b4 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/LiquibaseChangelogMissingFailureAnalyzer.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/LiquibaseChangelogMissingFailureAnalyzer.java
@@ -17,6 +17,7 @@
 package org.springframework.boot.liquibase;
 
 import liquibase.exception.ChangeLogParseException;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.boot.diagnostics.AbstractFailureAnalyzer;
 import org.springframework.boot.diagnostics.FailureAnalysis;
@@ -32,17 +33,18 @@ class LiquibaseChangelogMissingFailureAnalyzer extends AbstractFailureAnalyzer<C
 	private static final String MESSAGE_SUFFIX = " does not exist";
 
 	@Override
-	protected FailureAnalysis analyze(Throwable rootFailure, ChangeLogParseException cause) {
-		if (cause.getMessage().endsWith(MESSAGE_SUFFIX)) {
-			String changelogPath = extractChangelogPath(cause);
+	protected @Nullable FailureAnalysis analyze(Throwable rootFailure, ChangeLogParseException cause) {
+		String message = cause.getMessage();
+		if (message != null && message.endsWith(MESSAGE_SUFFIX)) {
+			String changelogPath = extractChangelogPath(message);
 			return new FailureAnalysis(getDescription(changelogPath),
 					"Make sure a Liquibase changelog is present at the configured path.", cause);
 		}
 		return null;
 	}
 
-	private String extractChangelogPath(ChangeLogParseException cause) {
-		return cause.getMessage().substring(0, cause.getMessage().length() - MESSAGE_SUFFIX.length());
+	private String extractChangelogPath(String message) {
+		return message.substring(0, message.length() - MESSAGE_SUFFIX.length());
 	}
 
 	private String getDescription(String changelogPath) {
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseAutoConfiguration.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseAutoConfiguration.java
index d3a13a9599a..d6a11b4f415 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseAutoConfiguration.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseAutoConfiguration.java
@@ -25,6 +25,7 @@ import liquibase.change.DatabaseChange;
 import liquibase.integration.spring.Customizer;
 import liquibase.integration.spring.SpringLiquibase;
 import liquibase.ui.UIServiceEnum;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
@@ -142,8 +143,8 @@ public final class LiquibaseAutoConfiguration {
 			return liquibase;
 		}
 
-		private SpringLiquibase createSpringLiquibase(DataSource liquibaseDataSource, DataSource dataSource,
-				LiquibaseConnectionDetails connectionDetails) {
+		private SpringLiquibase createSpringLiquibase(@Nullable DataSource liquibaseDataSource,
+				@Nullable DataSource dataSource, LiquibaseConnectionDetails connectionDetails) {
 			DataSource migrationDataSource = getMigrationDataSource(liquibaseDataSource, dataSource, connectionDetails);
 			SpringLiquibase liquibase = (migrationDataSource == liquibaseDataSource
 					|| migrationDataSource == dataSource) ? new SpringLiquibase()
@@ -152,8 +153,8 @@ public final class LiquibaseAutoConfiguration {
 			return liquibase;
 		}
 
-		private DataSource getMigrationDataSource(DataSource liquibaseDataSource, DataSource dataSource,
-				LiquibaseConnectionDetails connectionDetails) {
+		private DataSource getMigrationDataSource(@Nullable DataSource liquibaseDataSource,
+				@Nullable DataSource dataSource, LiquibaseConnectionDetails connectionDetails) {
 			if (liquibaseDataSource != null) {
 				return liquibaseDataSource;
 			}
@@ -224,7 +225,7 @@ public final class LiquibaseAutoConfiguration {
 	static class LiquibaseAutoConfigurationRuntimeHints implements RuntimeHintsRegistrar {
 
 		@Override
-		public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
+		public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader) {
 			hints.resources().registerPattern("db/changelog/**");
 		}
 
@@ -242,22 +243,22 @@ public final class LiquibaseAutoConfiguration {
 		}
 
 		@Override
-		public String getUsername() {
+		public @Nullable String getUsername() {
 			return this.properties.getUser();
 		}
 
 		@Override
-		public String getPassword() {
+		public @Nullable String getPassword() {
 			return this.properties.getPassword();
 		}
 
 		@Override
-		public String getJdbcUrl() {
+		public @Nullable String getJdbcUrl() {
 			return this.properties.getUrl();
 		}
 
 		@Override
-		public String getDriverClassName() {
+		public @Nullable String getDriverClassName() {
 			String driverClassName = this.properties.getDriverClassName();
 			return (driverClassName != null) ? driverClassName : LiquibaseConnectionDetails.super.getDriverClassName();
 		}
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseConnectionDetails.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseConnectionDetails.java
index 5fdd97d4364..5be84609699 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseConnectionDetails.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseConnectionDetails.java
@@ -16,6 +16,8 @@
 
 package org.springframework.boot.liquibase.autoconfigure;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.autoconfigure.service.connection.ConnectionDetails;
 import org.springframework.boot.jdbc.DatabaseDriver;
 
@@ -32,21 +34,21 @@ public interface LiquibaseConnectionDetails extends ConnectionDetails {
 	 * required.
 	 * @return the username for the database or {@code null}
 	 */
-	String getUsername();
+	@Nullable String getUsername();
 
 	/**
 	 * Password for the database or {@code null} if no Liquibase-specific configuration is
 	 * required.
 	 * @return the password for the database or {@code null}
 	 */
-	String getPassword();
+	@Nullable String getPassword();
 
 	/**
 	 * JDBC URL for the database or {@code null} if no Liquibase-specific configuration is
 	 * required.
 	 * @return the JDBC URL for the database or {@code null}
 	 */
-	String getJdbcUrl();
+	@Nullable String getJdbcUrl();
 
 	/**
 	 * The name of the JDBC driver class. Defaults to the class name of the driver
@@ -56,7 +58,7 @@ public interface LiquibaseConnectionDetails extends ConnectionDetails {
 	 * @see DatabaseDriver#fromJdbcUrl(String)
 	 * @see DatabaseDriver#getDriverClassName()
 	 */
-	default String getDriverClassName() {
+	@Nullable default String getDriverClassName() {
 		String jdbcUrl = getJdbcUrl();
 		return (jdbcUrl != null) ? DatabaseDriver.fromJdbcUrl(jdbcUrl).getDriverClassName() : null;
 	}
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseProperties.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseProperties.java
index d3e2536e072..8b0dbd9a766 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseProperties.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/LiquibaseProperties.java
@@ -24,6 +24,7 @@ import liquibase.UpdateSummaryEnum;
 import liquibase.UpdateSummaryOutputEnum;
 import liquibase.integration.spring.SpringLiquibase;
 import liquibase.ui.UIServiceEnum;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.util.Assert;
@@ -54,22 +55,22 @@ public class LiquibaseProperties {
 	/**
 	 * List of runtime contexts to use.
 	 */
-	private List<String> contexts;
+	private @Nullable List<String> contexts;
 
 	/**
 	 * Default database schema.
 	 */
-	private String defaultSchema;
+	private @Nullable String defaultSchema;
 
 	/**
 	 * Schema to use for Liquibase objects.
 	 */
-	private String liquibaseSchema;
+	private @Nullable String liquibaseSchema;
 
 	/**
 	 * Tablespace to use for Liquibase objects.
 	 */
-	private String liquibaseTablespace;
+	private @Nullable String liquibaseTablespace;
 
 	/**
 	 * Name of table to use for tracking change history.
@@ -94,38 +95,38 @@ public class LiquibaseProperties {
 	/**
 	 * Login user of the database to migrate.
 	 */
-	private String user;
+	private @Nullable String user;
 
 	/**
 	 * Login password of the database to migrate.
 	 */
-	private String password;
+	private @Nullable String password;
 
 	/**
 	 * Fully qualified name of the JDBC driver. Auto-detected based on the URL by default.
 	 */
-	private String driverClassName;
+	private @Nullable String driverClassName;
 
 	/**
 	 * JDBC URL of the database to migrate. If not set, the primary configured data source
 	 * is used.
 	 */
-	private String url;
+	private @Nullable String url;
 
 	/**
 	 * List of runtime labels to use.
 	 */
-	private List<String> labelFilter;
+	private @Nullable List<String> labelFilter;
 
 	/**
 	 * Change log parameters.
 	 */
-	private Map<String, String> parameters;
+	private @Nullable Map<String, String> parameters;
 
 	/**
 	 * File to which rollback SQL is written when an update is performed.
 	 */
-	private File rollbackFile;
+	private @Nullable File rollbackFile;
 
 	/**
 	 * Whether rollback should be tested before update is performed.
@@ -137,32 +138,32 @@ public class LiquibaseProperties {
 	 * "rollbackFile" to generate a rollback script for all existing changes associated
 	 * with that tag.
 	 */
-	private String tag;
+	private @Nullable String tag;
 
 	/**
 	 * Whether to print a summary of the update operation.
 	 */
-	private ShowSummary showSummary;
+	private @Nullable ShowSummary showSummary;
 
 	/**
 	 * Where to print a summary of the update operation.
 	 */
-	private ShowSummaryOutput showSummaryOutput;
+	private @Nullable ShowSummaryOutput showSummaryOutput;
 
 	/**
 	 * Which UIService to use.
 	 */
-	private UiService uiService;
+	private @Nullable UiService uiService;
 
 	/**
 	 * Whether to send product usage data and analytics to Liquibase.
 	 */
-	private Boolean analyticsEnabled;
+	private @Nullable Boolean analyticsEnabled;
 
 	/**
 	 * Liquibase Pro license key.
 	 */
-	private String licenseKey;
+	private @Nullable String licenseKey;
 
 	public String getChangeLog() {
 		return this.changeLog;
@@ -173,35 +174,35 @@ public class LiquibaseProperties {
 		this.changeLog = changeLog;
 	}
 
-	public List<String> getContexts() {
+	public @Nullable List<String> getContexts() {
 		return this.contexts;
 	}
 
-	public void setContexts(List<String> contexts) {
+	public void setContexts(@Nullable List<String> contexts) {
 		this.contexts = contexts;
 	}
 
-	public String getDefaultSchema() {
+	public @Nullable String getDefaultSchema() {
 		return this.defaultSchema;
 	}
 
-	public void setDefaultSchema(String defaultSchema) {
+	public void setDefaultSchema(@Nullable String defaultSchema) {
 		this.defaultSchema = defaultSchema;
 	}
 
-	public String getLiquibaseSchema() {
+	public @Nullable String getLiquibaseSchema() {
 		return this.liquibaseSchema;
 	}
 
-	public void setLiquibaseSchema(String liquibaseSchema) {
+	public void setLiquibaseSchema(@Nullable String liquibaseSchema) {
 		this.liquibaseSchema = liquibaseSchema;
 	}
 
-	public String getLiquibaseTablespace() {
+	public @Nullable String getLiquibaseTablespace() {
 		return this.liquibaseTablespace;
 	}
 
-	public void setLiquibaseTablespace(String liquibaseTablespace) {
+	public void setLiquibaseTablespace(@Nullable String liquibaseTablespace) {
 		this.liquibaseTablespace = liquibaseTablespace;
 	}
 
@@ -245,59 +246,59 @@ public class LiquibaseProperties {
 		this.enabled = enabled;
 	}
 
-	public String getUser() {
+	public @Nullable String getUser() {
 		return this.user;
 	}
 
-	public void setUser(String user) {
+	public void setUser(@Nullable String user) {
 		this.user = user;
 	}
 
-	public String getPassword() {
+	public @Nullable String getPassword() {
 		return this.password;
 	}
 
-	public void setPassword(String password) {
+	public void setPassword(@Nullable String password) {
 		this.password = password;
 	}
 
-	public String getDriverClassName() {
+	public @Nullable String getDriverClassName() {
 		return this.driverClassName;
 	}
 
-	public void setDriverClassName(String driverClassName) {
+	public void setDriverClassName(@Nullable String driverClassName) {
 		this.driverClassName = driverClassName;
 	}
 
-	public String getUrl() {
+	public @Nullable String getUrl() {
 		return this.url;
 	}
 
-	public void setUrl(String url) {
+	public void setUrl(@Nullable String url) {
 		this.url = url;
 	}
 
-	public List<String> getLabelFilter() {
+	public @Nullable List<String> getLabelFilter() {
 		return this.labelFilter;
 	}
 
-	public void setLabelFilter(List<String> labelFilter) {
+	public void setLabelFilter(@Nullable List<String> labelFilter) {
 		this.labelFilter = labelFilter;
 	}
 
-	public Map<String, String> getParameters() {
+	public @Nullable Map<String, String> getParameters() {
 		return this.parameters;
 	}
 
-	public void setParameters(Map<String, String> parameters) {
+	public void setParameters(@Nullable Map<String, String> parameters) {
 		this.parameters = parameters;
 	}
 
-	public File getRollbackFile() {
+	public @Nullable File getRollbackFile() {
 		return this.rollbackFile;
 	}
 
-	public void setRollbackFile(File rollbackFile) {
+	public void setRollbackFile(@Nullable File rollbackFile) {
 		this.rollbackFile = rollbackFile;
 	}
 
@@ -309,51 +310,51 @@ public class LiquibaseProperties {
 		this.testRollbackOnUpdate = testRollbackOnUpdate;
 	}
 
-	public String getTag() {
+	public @Nullable String getTag() {
 		return this.tag;
 	}
 
-	public void setTag(String tag) {
+	public void setTag(@Nullable String tag) {
 		this.tag = tag;
 	}
 
-	public ShowSummary getShowSummary() {
+	public @Nullable ShowSummary getShowSummary() {
 		return this.showSummary;
 	}
 
-	public void setShowSummary(ShowSummary showSummary) {
+	public void setShowSummary(@Nullable ShowSummary showSummary) {
 		this.showSummary = showSummary;
 	}
 
-	public ShowSummaryOutput getShowSummaryOutput() {
+	public @Nullable ShowSummaryOutput getShowSummaryOutput() {
 		return this.showSummaryOutput;
 	}
 
-	public void setShowSummaryOutput(ShowSummaryOutput showSummaryOutput) {
+	public void setShowSummaryOutput(@Nullable ShowSummaryOutput showSummaryOutput) {
 		this.showSummaryOutput = showSummaryOutput;
 	}
 
-	public UiService getUiService() {
+	public @Nullable UiService getUiService() {
 		return this.uiService;
 	}
 
-	public void setUiService(UiService uiService) {
+	public void setUiService(@Nullable UiService uiService) {
 		this.uiService = uiService;
 	}
 
-	public Boolean getAnalyticsEnabled() {
+	public @Nullable Boolean getAnalyticsEnabled() {
 		return this.analyticsEnabled;
 	}
 
-	public void setAnalyticsEnabled(Boolean analyticsEnabled) {
+	public void setAnalyticsEnabled(@Nullable Boolean analyticsEnabled) {
 		this.analyticsEnabled = analyticsEnabled;
 	}
 
-	public String getLicenseKey() {
+	public @Nullable String getLicenseKey() {
 		return this.licenseKey;
 	}
 
-	public void setLicenseKey(String licenseKey) {
+	public void setLicenseKey(@Nullable String licenseKey) {
 		this.licenseKey = licenseKey;
 	}
 
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/endpoint/package-info.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/endpoint/package-info.java
index 02c03c333ef..31161af0676 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/endpoint/package-info.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/endpoint/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Auto-configuration for Liquibase endpoint.
  */
+@NullMarked
 package org.springframework.boot.liquibase.autoconfigure.endpoint;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/package-info.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/package-info.java
index 11e1da2a4a7..548c8a62853 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/package-info.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/autoconfigure/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Auto-configuration for Liquibase.
  */
+@NullMarked
 package org.springframework.boot.liquibase.autoconfigure;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/JdbcAdaptingLiquibaseConnectionDetailsFactory.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/JdbcAdaptingLiquibaseConnectionDetailsFactory.java
index 3bd6b99f040..df9d6842bf5 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/JdbcAdaptingLiquibaseConnectionDetailsFactory.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/JdbcAdaptingLiquibaseConnectionDetailsFactory.java
@@ -16,6 +16,8 @@
 
 package org.springframework.boot.liquibase.docker.compose;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.autoconfigure.service.connection.ConnectionDetailsFactory;
 import org.springframework.boot.jdbc.autoconfigure.JdbcConnectionDetails;
 import org.springframework.boot.liquibase.autoconfigure.LiquibaseConnectionDetails;
@@ -34,12 +36,12 @@ class JdbcAdaptingLiquibaseConnectionDetailsFactory
 		return new LiquibaseConnectionDetails() {
 
 			@Override
-			public String getUsername() {
+			public @Nullable String getUsername() {
 				return input.getUsername();
 			}
 
 			@Override
-			public String getPassword() {
+			public @Nullable String getPassword() {
 				return input.getPassword();
 			}
 
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/package-info.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/package-info.java
index 85c2ab397df..7ad64ee5dd7 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/package-info.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/docker/compose/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Support for Docker Compose Liquibase service connections.
  */
+@NullMarked
 package org.springframework.boot.liquibase.docker.compose;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/LiquibaseEndpoint.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/LiquibaseEndpoint.java
index 6469f592210..737c1461a20 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/LiquibaseEndpoint.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/LiquibaseEndpoint.java
@@ -31,6 +31,7 @@ import liquibase.database.Database;
 import liquibase.database.DatabaseFactory;
 import liquibase.database.jvm.JdbcConnection;
 import liquibase.integration.spring.SpringLiquibase;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.boot.actuate.endpoint.OperationResponseBody;
 import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
@@ -128,9 +129,10 @@ public class LiquibaseEndpoint {
 
 		private final Map<String, LiquibaseBeanDescriptor> liquibaseBeans;
 
-		private final String parentId;
+		private final @Nullable String parentId;
 
-		private ContextLiquibaseBeansDescriptor(Map<String, LiquibaseBeanDescriptor> liquibaseBeans, String parentId) {
+		private ContextLiquibaseBeansDescriptor(Map<String, LiquibaseBeanDescriptor> liquibaseBeans,
+				@Nullable String parentId) {
 			this.liquibaseBeans = liquibaseBeans;
 			this.parentId = parentId;
 		}
@@ -139,7 +141,7 @@ public class LiquibaseEndpoint {
 			return this.liquibaseBeans;
 		}
 
-		public String getParentId() {
+		public @Nullable String getParentId() {
 			return this.parentId;
 		}
 
@@ -187,7 +189,7 @@ public class LiquibaseEndpoint {
 
 		private final Set<String> labels;
 
-		private final String checksum;
+		private final @Nullable String checksum;
 
 		private final Integer orderExecuted;
 
@@ -250,7 +252,7 @@ public class LiquibaseEndpoint {
 			return this.labels;
 		}
 
-		public String getChecksum() {
+		public @Nullable String getChecksum() {
 			return this.checksum;
 		}
 
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/package-info.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/package-info.java
index 539140b4eba..5d9e03bd954 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/package-info.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/endpoint/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Actuator endpoint for Liquibase.
  */
+@NullMarked
 package org.springframework.boot.liquibase.endpoint;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/package-info.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/package-info.java
index 3aa5878b28b..b5289ac8050 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/package-info.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Custom support for Liquibase database migration.
  */
+@NullMarked
 package org.springframework.boot.liquibase;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/testcontainers/package-info.java b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/testcontainers/package-info.java
index ca59b899a86..38da273afbb 100644
--- a/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/testcontainers/package-info.java
+++ b/module/spring-boot-liquibase/src/main/java/org/springframework/boot/liquibase/testcontainers/package-info.java
@@ -17,4 +17,7 @@
 /**
  * Support for testcontainers Liquibase service connections.
  */
+@NullMarked
 package org.springframework.boot.liquibase.testcontainers;
+
+import org.jspecify.annotations.NullMarked;