diff --git a/gradle/java-module.gradle b/gradle/java-module.gradle
index 35e64e922bea..dc69765cf824 100644
--- a/gradle/java-module.gradle
+++ b/gradle/java-module.gradle
@@ -524,7 +524,7 @@ checkerFramework {
 	extraJavacArgs = [
 	        '-AsuppressWarnings=initialization',
 			"-Astubs=${project.rootDir}/checkerstubs",
-			'-AonlyDefs=^org\\.hibernate\\.jpamodelgen\\.'
+			'-AonlyDefs=^org\\.hibernate\\.(jpamodelgen|spi)\\.'
 	]
 }
 
diff --git a/hibernate-core/src/main/java/org/hibernate/internal/util/StringHelper.java b/hibernate-core/src/main/java/org/hibernate/internal/util/StringHelper.java
index a3b39499b041..8ffc02b9e59b 100644
--- a/hibernate-core/src/main/java/org/hibernate/internal/util/StringHelper.java
+++ b/hibernate-core/src/main/java/org/hibernate/internal/util/StringHelper.java
@@ -20,6 +20,8 @@
 import org.hibernate.internal.util.collections.ArrayHelper;
 import org.hibernate.loader.internal.AliasConstantsHelper;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 public final class StringHelper {
 
 	private static final int ALIAS_TRUNCATE_LENGTH = 10;
@@ -825,7 +827,7 @@ public static String[] unquote(final String[] names, final Dialect dialect) {
 		}
 	}
 
-	public static String nullIfEmpty(String value) {
+	public static String nullIfEmpty(@Nullable String value) {
 		return isEmpty( value ) ? null : value;
 	}
 
diff --git a/hibernate-core/src/main/java/org/hibernate/spi/DotIdentifierSequence.java b/hibernate-core/src/main/java/org/hibernate/spi/DotIdentifierSequence.java
index 7f5aedb01cd5..ec160fed4faf 100644
--- a/hibernate-core/src/main/java/org/hibernate/spi/DotIdentifierSequence.java
+++ b/hibernate-core/src/main/java/org/hibernate/spi/DotIdentifierSequence.java
@@ -9,7 +9,9 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import org.hibernate.metamodel.mapping.SelectablePath;
+import org.hibernate.internal.util.NullnessUtil;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * A compound name.
@@ -26,7 +28,7 @@ public interface DotIdentifierSequence {
 	 * Given the sequence {@code a.b.c}, returns the sequence
 	 * {@code a.b}.
 	 */
-	DotIdentifierSequence getParent();
+	@Nullable DotIdentifierSequence getParent();
 
 	/**
 	 * The name of this leaf sequence part.
@@ -64,8 +66,9 @@ default DotIdentifierSequence[] getParts() {
 	}
 
 	private void parts(List<DotIdentifierSequence> list) {
-		if ( getParent() != null ) {
-			getParent().parts( list );
+		DotIdentifierSequence parent = getParent();
+		if ( parent != null ) {
+			parent.parts( list );
 		}
 		list.add( this );
 	}
diff --git a/hibernate-core/src/main/java/org/hibernate/spi/NavigablePath.java b/hibernate-core/src/main/java/org/hibernate/spi/NavigablePath.java
index 1d6d058f312a..bb34c268307b 100644
--- a/hibernate-core/src/main/java/org/hibernate/spi/NavigablePath.java
+++ b/hibernate-core/src/main/java/org/hibernate/spi/NavigablePath.java
@@ -12,6 +12,10 @@
 import org.hibernate.Incubating;
 import org.hibernate.internal.util.StringHelper;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import static org.hibernate.internal.util.NullnessUtil.castNonNull;
+
 /**
  * A compound name where the root path element is an entity name or a collection role
  * and each the path sub-path from the root references a domain or mapping model part
@@ -23,9 +27,9 @@
 public class NavigablePath implements DotIdentifierSequence, Serializable {
 	public static final String IDENTIFIER_MAPPER_PROPERTY = "_identifierMapper";
 
-	private final NavigablePath parent;
+	private final @Nullable NavigablePath parent;
 	private final String localName;
-	private final String alias;
+	private final @Nullable String alias;
 	private final String identifierForTableGroup;
 	private final FullPathCalculator fullPathCalculator;
 	private final int hashCode;
@@ -34,7 +38,7 @@ public NavigablePath(String localName) {
 		this( localName, null );
 	}
 
-	public NavigablePath(String rootName, String alias) {
+	public NavigablePath(String rootName, @Nullable String alias) {
 		this.parent = null;
 		this.alias = alias = StringHelper.nullIfEmpty( alias );
 		this.localName = rootName;
@@ -49,7 +53,7 @@ public NavigablePath(NavigablePath parent, String navigableName) {
 		this( parent, navigableName, null );
 	}
 
-	public NavigablePath(NavigablePath parent, String localName, String alias) {
+	public NavigablePath(NavigablePath parent, String localName, @Nullable String alias) {
 		assert parent != null;
 
 		this.parent = parent;
@@ -79,9 +83,9 @@ public NavigablePath(NavigablePath parent, String localName, String alias) {
 	}
 
 	public NavigablePath(
-			NavigablePath parent,
+			@Nullable NavigablePath parent,
 			String localName,
-			String alias,
+			@Nullable String alias,
 			String identifierForTableGroup,
 			FullPathCalculator fullPathCalculator,
 			int hashCode) {
@@ -94,7 +98,7 @@ public NavigablePath(
 	}
 
 	@Override
-	public NavigablePath getParent() {
+	public @Nullable NavigablePath getParent() {
 		return parent instanceof TreatedNavigablePath ? parent.getParent() : parent;
 	}
 
@@ -103,7 +107,7 @@ public String getLocalName() {
 		return localName;
 	}
 
-	public String getAlias() {
+	public @Nullable String getAlias() {
 		return alias;
 	}
 
@@ -121,7 +125,7 @@ public int hashCode() {
 	}
 
 	@Override
-	public boolean equals(Object other) {
+	public boolean equals(@Nullable Object other) {
 		if ( this == other ) {
 			return true;
 		}
@@ -175,14 +179,14 @@ public NavigablePath treatAs(String entityName, String alias) {
 		return new TreatedNavigablePath( this, entityName, alias );
 	}
 
-	public NavigablePath getRealParent() {
+	public @Nullable NavigablePath getRealParent() {
 		return parent;
 	}
 
 	/**
 	 * Determine whether this path is part of the given path's parent
 	 */
-	public boolean isParent(NavigablePath navigablePath) {
+	public boolean isParent(@Nullable NavigablePath navigablePath) {
 		while ( navigablePath != null ) {
 			if ( this.equals( navigablePath.getParent() ) ) {
 				return true;
@@ -195,14 +199,15 @@ public boolean isParent(NavigablePath navigablePath) {
 	/**
 	 * Determine whether the given path is a suffix of this path
 	 */
-	public boolean isSuffix(DotIdentifierSequence dotIdentifierSequence) {
+	public boolean isSuffix(@Nullable DotIdentifierSequence dotIdentifierSequence) {
 		if ( dotIdentifierSequence == null ) {
 			return true;
 		}
 		if ( !localNamesMatch( dotIdentifierSequence ) ) {
 			return false;
 		}
-		return getParent() != null && getParent().isSuffix( dotIdentifierSequence.getParent() );
+		NavigablePath parent = getParent();
+		return parent != null && parent.isSuffix( dotIdentifierSequence.getParent() );
 	}
 
 	/**
@@ -216,15 +221,16 @@ public boolean isSuffix(DotIdentifierSequence dotIdentifierSequence) {
 	 * or null if the NavigablePath does not contain the suffix.
 	 *
 	 */
-	public NavigablePath trimSuffix(DotIdentifierSequence suffix) {
+	public @Nullable NavigablePath trimSuffix(@Nullable DotIdentifierSequence suffix) {
 		if ( suffix == null ) {
 			return this;
 		}
 		if ( !getLocalName().equals( suffix.getLocalName() ) ) {
 			return null;
 		}
-		if ( getParent() != null ) {
-			return getParent().trimSuffix( suffix.getParent() );
+		NavigablePath parent = getParent();
+		if ( parent != null ) {
+			return parent.trimSuffix( suffix.getParent() );
 		}
 		return null;
 	}
@@ -232,7 +238,7 @@ public NavigablePath trimSuffix(DotIdentifierSequence suffix) {
 	/**
 	 * Determine whether this path is part of the given path's parent
 	 */
-	public boolean isParentOrEqual(NavigablePath navigablePath) {
+	public boolean isParentOrEqual(@Nullable NavigablePath navigablePath) {
 		while ( navigablePath != null ) {
 			if ( this.equals( navigablePath ) ) {
 				return true;
@@ -242,7 +248,7 @@ public boolean isParentOrEqual(NavigablePath navigablePath) {
 		return false;
 	}
 
-	public boolean pathsMatch(NavigablePath p) {
+	public boolean pathsMatch(@Nullable NavigablePath p) {
 		return this == p || p != null && localName.equals( p.localName )
 				&& ( parent == null ? p.parent == null && Objects.equals( alias, p.alias ) : parent.pathsMatch( p.parent ) );
 	}
@@ -250,7 +256,7 @@ public boolean pathsMatch(NavigablePath p) {
 	/**
 	 * Ignores aliases in the resulting String
 	 */
-	public String relativize(NavigablePath base) {
+	public @Nullable String relativize(NavigablePath base) {
 		// e.g.
 		//	- base = Root.sub
 		//	- this = Root.sub.stuff
@@ -284,7 +290,7 @@ public void collectPath(String path) {
 			buffer.append( path );
 		}
 
-		public String resolve() {
+		public @Nullable String resolve() {
 			if ( buffer == null ) {
 				// Return an empty string instead of null in case the two navigable paths are equal
 				return matchedBase ? "" : null;
@@ -323,13 +329,13 @@ public String toString() {
 	 */
 	@FunctionalInterface
 	protected interface FullPathCalculator extends Serializable {
-		String calculateFullPath(NavigablePath parent, String localName, String alias);
+		String calculateFullPath(@Nullable NavigablePath parent, String localName, @Nullable String alias);
 	}
 
 	/**
 	 * The pattern used for root NavigablePaths
 	 */
-	protected static String calculateRootFullPath(NavigablePath parent, String rootName, String alias) {
+	protected static String calculateRootFullPath(@Nullable NavigablePath parent, String rootName, @Nullable String alias) {
 		assert parent == null;
 		return alias == null ? rootName : rootName + "(" + alias + ")";
 	}
@@ -337,10 +343,10 @@ protected static String calculateRootFullPath(NavigablePath parent, String rootN
 	/**
 	 * The normal pattern used for the "full path"
 	 */
-	private static String calculateNormalFullPath(NavigablePath parent, String localName, String alias) {
+	private static String calculateNormalFullPath(@Nullable NavigablePath parent, String localName, @Nullable String alias) {
 		assert parent != null;
 
-		final String parentFullPath = parent.getFullPath();
+		final String parentFullPath = castNonNull( parent ).getFullPath();
 		final String baseFullPath = StringHelper.isEmpty( parentFullPath )
 				? localName
 				: parentFullPath + "." + localName;
@@ -350,7 +356,7 @@ private static String calculateNormalFullPath(NavigablePath parent, String local
 	/**
 	 * Pattern used for `_identifierMapper`
 	 */
-	protected static String calculateIdMapperFullPath(NavigablePath parent, String localName, String alias) {
+	protected static String calculateIdMapperFullPath(@Nullable NavigablePath parent, String localName, @Nullable String alias) {
 		return parent != null ? parent.getFullPath() : "";
 	}
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/spi/TreatedNavigablePath.java b/hibernate-core/src/main/java/org/hibernate/spi/TreatedNavigablePath.java
index 117d9a33cc6d..223c4a904c0f 100644
--- a/hibernate-core/src/main/java/org/hibernate/spi/TreatedNavigablePath.java
+++ b/hibernate-core/src/main/java/org/hibernate/spi/TreatedNavigablePath.java
@@ -8,6 +8,10 @@
 
 import org.hibernate.Incubating;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import static org.hibernate.internal.util.NullnessUtil.castNonNull;
+
 /**
  * An implementation of {@link NavigablePath} with special handling for treated paths.
  *
@@ -20,7 +24,7 @@ public TreatedNavigablePath(NavigablePath parent, String entityTypeName) {
 		this( parent, entityTypeName, null );
 	}
 
-	public TreatedNavigablePath(NavigablePath parent, String entityTypeName, String alias) {
+	public TreatedNavigablePath(NavigablePath parent, String entityTypeName, @Nullable String alias) {
 		super(
 				parent,
 				"#" + entityTypeName,
@@ -32,7 +36,7 @@ public TreatedNavigablePath(NavigablePath parent, String entityTypeName, String
 		assert !( parent instanceof TreatedNavigablePath );
 	}
 
-	protected static String calculateTreatedFullPath(NavigablePath parent, String localName, String alias) {
+	protected static String calculateTreatedFullPath(@Nullable NavigablePath parent, String localName, @Nullable String alias) {
 		return alias == null
 				? "treat(" + parent + " as " + localName + ")"
 				: "treat(" + parent + " as " + localName + ")(" + alias + ")";
@@ -40,12 +44,12 @@ protected static String calculateTreatedFullPath(NavigablePath parent, String lo
 
 	@Override
 	public NavigablePath treatAs(String entityName) {
-		return new TreatedNavigablePath( getRealParent(), entityName );
+		return new TreatedNavigablePath( castNonNull( getRealParent() ), entityName );
 	}
 
 	@Override
 	public NavigablePath treatAs(String entityName, String alias) {
-		return new TreatedNavigablePath( getRealParent(), entityName, alias );
+		return new TreatedNavigablePath( castNonNull( getRealParent() ), entityName, alias );
 	}
 
 //	@Override