Finish migrating to JSpecify annotations

PiperOrigin-RevId: 397209445

84 files changed, 84 insertions, 73 deletions

diff --git a/java/com/google/common/escape/package-info.java b/java/com/google/common/escape/package-info.java
index 1683da4..b69b34e 100644
--- a/java/com/google/common/escape/package-info.java
+++ b/java/com/google/common/escape/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.common.escape;
diff --git a/java/com/google/turbine/binder/Binder.java b/java/com/google/turbine/binder/Binder.java
index 9ac76f5..2916a81 100644
--- a/java/com/google/turbine/binder/Binder.java
+++ b/java/com/google/turbine/binder/Binder.java
@@ -69,7 +69,7 @@ import com.google.turbine.type.Type;
 import java.time.Duration;
 import java.util.Optional;
 import javax.annotation.processing.Processor;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** The entry point for analysis. */
 public final class Binder {
diff --git a/java/com/google/turbine/binder/ClassPath.java b/java/com/google/turbine/binder/ClassPath.java
index e2cc30e..eb78099 100644
--- a/java/com/google/turbine/binder/ClassPath.java
+++ b/java/com/google/turbine/binder/ClassPath.java
@@ -23,7 +23,7 @@ import com.google.turbine.binder.env.Env;
 import com.google.turbine.binder.lookup.TopLevelIndex;
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.binder.sym.ModuleSymbol;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A compilation classpath, e.g. the user or platform class path. May be backed by a search path of
diff --git a/java/com/google/turbine/binder/ClassPathBinder.java b/java/com/google/turbine/binder/ClassPathBinder.java
index ba8cd8a..1c41e96 100644
--- a/java/com/google/turbine/binder/ClassPathBinder.java
+++ b/java/com/google/turbine/binder/ClassPathBinder.java
@@ -36,7 +36,7 @@ import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Sets up an environment for symbols on the classpath. */
 public final class ClassPathBinder {
diff --git a/java/com/google/turbine/binder/ConstBinder.java b/java/com/google/turbine/binder/ConstBinder.java
index 96c03db..5f26ddc 100644
--- a/java/com/google/turbine/binder/ConstBinder.java
+++ b/java/com/google/turbine/binder/ConstBinder.java
@@ -57,7 +57,7 @@ import com.google.turbine.type.Type.WildUnboundedTy;
 import com.google.turbine.type.Type.WildUpperBoundedTy;
 import java.lang.annotation.RetentionPolicy;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Binding pass to evaluate constant expressions. */
 public class ConstBinder {
diff --git a/java/com/google/turbine/binder/ConstEvaluator.java b/java/com/google/turbine/binder/ConstEvaluator.java
index 1569e0b..d26667d 100644
--- a/java/com/google/turbine/binder/ConstEvaluator.java
+++ b/java/com/google/turbine/binder/ConstEvaluator.java
@@ -74,7 +74,7 @@ import java.util.ArrayDeque;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * Constant expression evaluation.
diff --git a/java/com/google/turbine/binder/CtSymClassBinder.java b/java/com/google/turbine/binder/CtSymClassBinder.java
index 2ba57be..f687de9 100644
--- a/java/com/google/turbine/binder/CtSymClassBinder.java
+++ b/java/com/google/turbine/binder/CtSymClassBinder.java
@@ -42,7 +42,7 @@ import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.HashMap;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Constructs a platform {@link ClassPath} from the current JDK's ct.sym file. */
 public final class CtSymClassBinder {
diff --git a/java/com/google/turbine/binder/FileManagerClassBinder.java b/java/com/google/turbine/binder/FileManagerClassBinder.java
index f5a2b61..d36d2d8 100644
--- a/java/com/google/turbine/binder/FileManagerClassBinder.java
+++ b/java/com/google/turbine/binder/FileManagerClassBinder.java
@@ -40,7 +40,7 @@ import javax.tools.FileObject;
 import javax.tools.JavaFileObject;
 import javax.tools.StandardJavaFileManager;
 import javax.tools.StandardLocation;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * Binds a {@link StandardJavaFileManager} to an {@link ClassPath}. This can be used to share a
diff --git a/java/com/google/turbine/binder/HierarchyBinder.java b/java/com/google/turbine/binder/HierarchyBinder.java
index 55b24da..2d33613 100644
--- a/java/com/google/turbine/binder/HierarchyBinder.java
+++ b/java/com/google/turbine/binder/HierarchyBinder.java
@@ -34,7 +34,7 @@ import com.google.turbine.model.TurbineTyKind;
 import com.google.turbine.tree.Tree;
 import com.google.turbine.tree.Tree.ClassTy;
 import java.util.ArrayDeque;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Type hierarchy binding. */
 public class HierarchyBinder {
diff --git a/java/com/google/turbine/binder/JimageClassBinder.java b/java/com/google/turbine/binder/JimageClassBinder.java
index 87d0640..0c17f2f 100644
--- a/java/com/google/turbine/binder/JimageClassBinder.java
+++ b/java/com/google/turbine/binder/JimageClassBinder.java
@@ -53,7 +53,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Constructs a platform {@link ClassPath} from the current JDK's jimage file using jrtfs. */
 public class JimageClassBinder {
diff --git a/java/com/google/turbine/binder/Processing.java b/java/com/google/turbine/binder/Processing.java
index 9bbf213..5e66577 100644
--- a/java/com/google/turbine/binder/Processing.java
+++ b/java/com/google/turbine/binder/Processing.java
@@ -74,7 +74,7 @@ import javax.annotation.processing.Processor;
 import javax.lang.model.SourceVersion;
 import javax.lang.model.element.TypeElement;
 import javax.tools.Diagnostic;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Top level annotation processing logic, see also {@link Binder}. */
 public class Processing {
diff --git a/java/com/google/turbine/binder/Resolve.java b/java/com/google/turbine/binder/Resolve.java
index cede5dd..6b76389 100644
--- a/java/com/google/turbine/binder/Resolve.java
+++ b/java/com/google/turbine/binder/Resolve.java
@@ -31,7 +31,7 @@ import com.google.turbine.tree.Tree;
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Qualified name resolution. */
 public final class Resolve {
diff --git a/java/com/google/turbine/binder/TypeBinder.java b/java/com/google/turbine/binder/TypeBinder.java
index 8cda0e3..ecb8ea7 100644
--- a/java/com/google/turbine/binder/TypeBinder.java
+++ b/java/com/google/turbine/binder/TypeBinder.java
@@ -63,7 +63,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Type binding. */
 public class TypeBinder {
diff --git a/java/com/google/turbine/binder/bound/AnnotationMetadata.java b/java/com/google/turbine/binder/bound/AnnotationMetadata.java
index c83eb0f..5ae04b0 100644
--- a/java/com/google/turbine/binder/bound/AnnotationMetadata.java
+++ b/java/com/google/turbine/binder/bound/AnnotationMetadata.java
@@ -23,7 +23,7 @@ import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.model.TurbineElementType;
 import java.lang.annotation.RetentionPolicy;
 import java.util.EnumSet;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * Annotation metadata, e.g. from {@link java.lang.annotation.Target}, {@link
diff --git a/java/com/google/turbine/binder/bound/BoundClass.java b/java/com/google/turbine/binder/bound/BoundClass.java
index 61dee0f..1e29b42 100644
--- a/java/com/google/turbine/binder/bound/BoundClass.java
+++ b/java/com/google/turbine/binder/bound/BoundClass.java
@@ -19,7 +19,7 @@ package com.google.turbine.binder.bound;
 import com.google.common.collect.ImmutableMap;
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.model.TurbineTyKind;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * The initial bound tree representation.
diff --git a/java/com/google/turbine/binder/bound/EnumConstantValue.java b/java/com/google/turbine/binder/bound/EnumConstantValue.java
index 5bdcd4a..20a5756 100644
--- a/java/com/google/turbine/binder/bound/EnumConstantValue.java
+++ b/java/com/google/turbine/binder/bound/EnumConstantValue.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.bound;
 
 import com.google.turbine.binder.sym.FieldSymbol;
 import com.google.turbine.model.Const;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An enum constant. */
 public class EnumConstantValue extends Const {
diff --git a/java/com/google/turbine/binder/bound/HeaderBoundClass.java b/java/com/google/turbine/binder/bound/HeaderBoundClass.java
index 45c87ac..9658016 100644
--- a/java/com/google/turbine/binder/bound/HeaderBoundClass.java
+++ b/java/com/google/turbine/binder/bound/HeaderBoundClass.java
@@ -20,7 +20,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.binder.sym.TyVarSymbol;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A bound node that augments {@link BoundClass} with superclasses and interfaces. */
 public interface HeaderBoundClass extends BoundClass {
diff --git a/java/com/google/turbine/binder/bound/ModuleInfo.java b/java/com/google/turbine/binder/bound/ModuleInfo.java
index f3990fa..5eeed04 100644
--- a/java/com/google/turbine/binder/bound/ModuleInfo.java
+++ b/java/com/google/turbine/binder/bound/ModuleInfo.java
@@ -19,7 +19,7 @@ package com.google.turbine.binder.bound;
 import com.google.common.collect.ImmutableList;
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.type.AnnoInfo;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A bound module declaration (see JLS §7.7). */
 public class ModuleInfo {
diff --git a/java/com/google/turbine/binder/bound/PackageSourceBoundClass.java b/java/com/google/turbine/binder/bound/PackageSourceBoundClass.java
index 0fe80ad..77832f9 100644
--- a/java/com/google/turbine/binder/bound/PackageSourceBoundClass.java
+++ b/java/com/google/turbine/binder/bound/PackageSourceBoundClass.java
@@ -23,7 +23,7 @@ import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.diag.SourceFile;
 import com.google.turbine.model.TurbineTyKind;
 import com.google.turbine.tree.Tree;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link BoundClass} with shared lookup scopes for the current compilation unit and package. */
 public class PackageSourceBoundClass implements BoundClass {
diff --git a/java/com/google/turbine/binder/bound/SourceBoundClass.java b/java/com/google/turbine/binder/bound/SourceBoundClass.java
index a05d318..7a6f33f 100644
--- a/java/com/google/turbine/binder/bound/SourceBoundClass.java
+++ b/java/com/google/turbine/binder/bound/SourceBoundClass.java
@@ -20,7 +20,7 @@ import com.google.common.collect.ImmutableMap;
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.model.TurbineTyKind;
 import com.google.turbine.tree.Tree;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link BoundClass} that corresponds to a source file being compiled. */
 public class SourceBoundClass implements BoundClass {
diff --git a/java/com/google/turbine/binder/bound/SourceHeaderBoundClass.java b/java/com/google/turbine/binder/bound/SourceHeaderBoundClass.java
index 5dfa808..210ff0b 100644
--- a/java/com/google/turbine/binder/bound/SourceHeaderBoundClass.java
+++ b/java/com/google/turbine/binder/bound/SourceHeaderBoundClass.java
@@ -25,7 +25,7 @@ import com.google.turbine.binder.sym.TyVarSymbol;
 import com.google.turbine.diag.SourceFile;
 import com.google.turbine.model.TurbineTyKind;
 import com.google.turbine.tree.Tree;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link HeaderBoundClass} that corresponds to a source file being compiled. */
 public class SourceHeaderBoundClass implements HeaderBoundClass {
diff --git a/java/com/google/turbine/binder/bound/SourceModuleInfo.java b/java/com/google/turbine/binder/bound/SourceModuleInfo.java
index 1163e9f..66ba0e4 100644
--- a/java/com/google/turbine/binder/bound/SourceModuleInfo.java
+++ b/java/com/google/turbine/binder/bound/SourceModuleInfo.java
@@ -24,7 +24,7 @@ import com.google.turbine.binder.bound.ModuleInfo.RequireInfo;
 import com.google.turbine.binder.bound.ModuleInfo.UseInfo;
 import com.google.turbine.diag.SourceFile;
 import com.google.turbine.type.AnnoInfo;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link ModuleInfo} that corresponds to a source file being compiled. */
 public class SourceModuleInfo extends ModuleInfo {
diff --git a/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java b/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java
index deceb42..cadd141 100644
--- a/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java
+++ b/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java
@@ -29,7 +29,7 @@ import com.google.turbine.type.AnnoInfo;
 import com.google.turbine.type.Type;
 import com.google.turbine.type.Type.ClassTy;
 import com.google.turbine.type.Type.TyKind;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A HeaderBoundClass for classes compiled from source. */
 public class SourceTypeBoundClass implements TypeBoundClass {
diff --git a/java/com/google/turbine/binder/bound/TurbineAnnotationValue.java b/java/com/google/turbine/binder/bound/TurbineAnnotationValue.java
index e502ff2..b6737d6 100644
--- a/java/com/google/turbine/binder/bound/TurbineAnnotationValue.java
+++ b/java/com/google/turbine/binder/bound/TurbineAnnotationValue.java
@@ -20,7 +20,7 @@ import com.google.common.collect.ImmutableMap;
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.model.Const;
 import com.google.turbine.type.AnnoInfo;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An annotation literal constant. */
 public class TurbineAnnotationValue extends Const {
diff --git a/java/com/google/turbine/binder/bound/TurbineClassValue.java b/java/com/google/turbine/binder/bound/TurbineClassValue.java
index b7a17a7..c6ba6ef 100644
--- a/java/com/google/turbine/binder/bound/TurbineClassValue.java
+++ b/java/com/google/turbine/binder/bound/TurbineClassValue.java
@@ -19,7 +19,7 @@ package com.google.turbine.binder.bound;
 import com.google.turbine.model.Const;
 import com.google.turbine.type.Type;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A class literal constant. */
 public class TurbineClassValue extends Const {
diff --git a/java/com/google/turbine/binder/bound/TypeBoundClass.java b/java/com/google/turbine/binder/bound/TypeBoundClass.java
index cf34ef1..5a14594 100644
--- a/java/com/google/turbine/binder/bound/TypeBoundClass.java
+++ b/java/com/google/turbine/binder/bound/TypeBoundClass.java
@@ -31,7 +31,7 @@ import com.google.turbine.type.AnnoInfo;
 import com.google.turbine.type.Type;
 import com.google.turbine.type.Type.IntersectionTy;
 import com.google.turbine.type.Type.MethodTy;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A bound node that augments {@link HeaderBoundClass} with type information. */
 public interface TypeBoundClass extends HeaderBoundClass {
diff --git a/java/com/google/turbine/binder/bound/package-info.java b/java/com/google/turbine/binder/bound/package-info.java
index 99a18d6..8839101 100644
--- a/java/com/google/turbine/binder/bound/package-info.java
+++ b/java/com/google/turbine/binder/bound/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.binder.bound;
diff --git a/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java b/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java
index 4a81316..83ecc0a 100644
--- a/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java
+++ b/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java
@@ -58,7 +58,7 @@ import com.google.turbine.type.Type.IntersectionTy;
 import java.lang.annotation.RetentionPolicy;
 import java.util.Map;
 import java.util.function.Function;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A bound class backed by a class file.
diff --git a/java/com/google/turbine/binder/bytecode/package-info.java b/java/com/google/turbine/binder/bytecode/package-info.java
index 23c59f0..d2d9708 100644
--- a/java/com/google/turbine/binder/bytecode/package-info.java
+++ b/java/com/google/turbine/binder/bytecode/package-info.java
@@ -14,4 +14,5 @@
  * limitations under the License.
  */
 
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.binder.bytecode;
diff --git a/java/com/google/turbine/binder/env/CompoundEnv.java b/java/com/google/turbine/binder/env/CompoundEnv.java
index 4b7cce6..391a2c3 100644
--- a/java/com/google/turbine/binder/env/CompoundEnv.java
+++ b/java/com/google/turbine/binder/env/CompoundEnv.java
@@ -19,7 +19,7 @@ package com.google.turbine.binder.env;
 import static java.util.Objects.requireNonNull;
 
 import com.google.turbine.binder.sym.Symbol;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An {@link Env} that chains two existing envs together. */
 public class CompoundEnv<S extends Symbol, V> implements Env<S, V> {
diff --git a/java/com/google/turbine/binder/env/Env.java b/java/com/google/turbine/binder/env/Env.java
index 17908e7..463c65d 100644
--- a/java/com/google/turbine/binder/env/Env.java
+++ b/java/com/google/turbine/binder/env/Env.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.env;
 
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.binder.sym.Symbol;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * An environment that maps {@link Symbol}s {@code S} to bound nodes {@code V}.
diff --git a/java/com/google/turbine/binder/env/LazyEnv.java b/java/com/google/turbine/binder/env/LazyEnv.java
index 35377a9..0b311f7 100644
--- a/java/com/google/turbine/binder/env/LazyEnv.java
+++ b/java/com/google/turbine/binder/env/LazyEnv.java
@@ -22,7 +22,7 @@ import com.google.turbine.binder.sym.Symbol;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * An env that permits an analysis pass to access information about symbols from the current pass,
diff --git a/java/com/google/turbine/binder/env/SimpleEnv.java b/java/com/google/turbine/binder/env/SimpleEnv.java
index d3537bf..9de5c9f 100644
--- a/java/com/google/turbine/binder/env/SimpleEnv.java
+++ b/java/com/google/turbine/binder/env/SimpleEnv.java
@@ -21,7 +21,7 @@ import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.turbine.binder.sym.Symbol;
 import java.util.LinkedHashMap;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A simple {@link ImmutableMap}-backed {@link Env}. */
 public class SimpleEnv<K extends Symbol, V> implements Env<K, V> {
diff --git a/java/com/google/turbine/binder/env/package-info.java b/java/com/google/turbine/binder/env/package-info.java
index e468029..fa57245 100644
--- a/java/com/google/turbine/binder/env/package-info.java
+++ b/java/com/google/turbine/binder/env/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.binder.env;
diff --git a/java/com/google/turbine/binder/lookup/CanonicalSymbolResolver.java b/java/com/google/turbine/binder/lookup/CanonicalSymbolResolver.java
index d85a273..d44f4e4 100644
--- a/java/com/google/turbine/binder/lookup/CanonicalSymbolResolver.java
+++ b/java/com/google/turbine/binder/lookup/CanonicalSymbolResolver.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.lookup;
 
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.tree.Tree;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Canonical type resolution. Breaks a circular dependency between binding and import handling. */
 public interface CanonicalSymbolResolver extends ImportScope.ResolveFunction {
diff --git a/java/com/google/turbine/binder/lookup/CompoundScope.java b/java/com/google/turbine/binder/lookup/CompoundScope.java
index 5b36288..17b923b 100644
--- a/java/com/google/turbine/binder/lookup/CompoundScope.java
+++ b/java/com/google/turbine/binder/lookup/CompoundScope.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.lookup;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link Scope} that chains other scopes together. */
 public class CompoundScope implements Scope {
diff --git a/java/com/google/turbine/binder/lookup/CompoundTopLevelIndex.java b/java/com/google/turbine/binder/lookup/CompoundTopLevelIndex.java
index 1d07797..16f34c3 100644
--- a/java/com/google/turbine/binder/lookup/CompoundTopLevelIndex.java
+++ b/java/com/google/turbine/binder/lookup/CompoundTopLevelIndex.java
@@ -19,7 +19,7 @@ package com.google.turbine.binder.lookup;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.common.collect.ImmutableList;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link TopLevelIndex} that aggregates multiple indices into one. */
 // Note: this implementation doesn't detect if the indices contain incompatible information,
diff --git a/java/com/google/turbine/binder/lookup/ImportIndex.java b/java/com/google/turbine/binder/lookup/ImportIndex.java
index 17a1caa..bcd9366 100644
--- a/java/com/google/turbine/binder/lookup/ImportIndex.java
+++ b/java/com/google/turbine/binder/lookup/ImportIndex.java
@@ -31,7 +31,7 @@ import com.google.turbine.tree.Tree.Ident;
 import com.google.turbine.tree.Tree.ImportDecl;
 import java.util.HashMap;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A scope that provides entries for the single-type imports in a compilation unit.
diff --git a/java/com/google/turbine/binder/lookup/ImportScope.java b/java/com/google/turbine/binder/lookup/ImportScope.java
index 8aadda4..a33a8e2 100644
--- a/java/com/google/turbine/binder/lookup/ImportScope.java
+++ b/java/com/google/turbine/binder/lookup/ImportScope.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.lookup;
 
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.tree.Tree;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A scope for imports. Non-canonical imports depend on hierarchy analysis, so to break the cycle we
diff --git a/java/com/google/turbine/binder/lookup/MemberImportIndex.java b/java/com/google/turbine/binder/lookup/MemberImportIndex.java
index 4155cfa..d825396 100644
--- a/java/com/google/turbine/binder/lookup/MemberImportIndex.java
+++ b/java/com/google/turbine/binder/lookup/MemberImportIndex.java
@@ -30,7 +30,7 @@ import com.google.turbine.tree.Tree.ImportDecl;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An index for statically imported members, in particular constant variables. */
 public class MemberImportIndex {
diff --git a/java/com/google/turbine/binder/lookup/PackageScope.java b/java/com/google/turbine/binder/lookup/PackageScope.java
index 695e802..94e950f 100644
--- a/java/com/google/turbine/binder/lookup/PackageScope.java
+++ b/java/com/google/turbine/binder/lookup/PackageScope.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.lookup;
 
 import com.google.common.collect.Iterables;
 import com.google.turbine.binder.sym.ClassSymbol;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A scope that corresponds to a particular package, which supports iteration over its enclosed
diff --git a/java/com/google/turbine/binder/lookup/Scope.java b/java/com/google/turbine/binder/lookup/Scope.java
index 12466f4..eb9f5cb 100644
--- a/java/com/google/turbine/binder/lookup/Scope.java
+++ b/java/com/google/turbine/binder/lookup/Scope.java
@@ -16,7 +16,7 @@
 
 package com.google.turbine.binder.lookup;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A scope that defines types, and supports qualified name resolution. */
 public interface Scope {
diff --git a/java/com/google/turbine/binder/lookup/SimpleTopLevelIndex.java b/java/com/google/turbine/binder/lookup/SimpleTopLevelIndex.java
index 1e2e465..4de0820 100644
--- a/java/com/google/turbine/binder/lookup/SimpleTopLevelIndex.java
+++ b/java/com/google/turbine/binder/lookup/SimpleTopLevelIndex.java
@@ -23,7 +23,7 @@ import com.google.turbine.binder.sym.ClassSymbol;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * An index of canonical type names where all members are known statically.
diff --git a/java/com/google/turbine/binder/lookup/TopLevelIndex.java b/java/com/google/turbine/binder/lookup/TopLevelIndex.java
index 77678f5..049ac5c 100644
--- a/java/com/google/turbine/binder/lookup/TopLevelIndex.java
+++ b/java/com/google/turbine/binder/lookup/TopLevelIndex.java
@@ -16,7 +16,7 @@
 
 package com.google.turbine.binder.lookup;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * An index of canonical type names.
diff --git a/java/com/google/turbine/binder/lookup/WildImportIndex.java b/java/com/google/turbine/binder/lookup/WildImportIndex.java
index 6709640..8b4bab1 100644
--- a/java/com/google/turbine/binder/lookup/WildImportIndex.java
+++ b/java/com/google/turbine/binder/lookup/WildImportIndex.java
@@ -22,7 +22,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.tree.Tree;
 import com.google.turbine.tree.Tree.ImportDecl;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A scope that provides best-effort lookup for on-demand imported types in a compilation unit.
diff --git a/java/com/google/turbine/binder/lookup/package-info.java b/java/com/google/turbine/binder/lookup/package-info.java
index b3ec8d0..7784138 100644
--- a/java/com/google/turbine/binder/lookup/package-info.java
+++ b/java/com/google/turbine/binder/lookup/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.binder.lookup;
diff --git a/java/com/google/turbine/binder/package-info.java b/java/com/google/turbine/binder/package-info.java
index bc3e320..9f550e0 100644
--- a/java/com/google/turbine/binder/package-info.java
+++ b/java/com/google/turbine/binder/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.binder;
diff --git a/java/com/google/turbine/binder/sym/ClassSymbol.java b/java/com/google/turbine/binder/sym/ClassSymbol.java
index 4e05767..45c9adf 100644
--- a/java/com/google/turbine/binder/sym/ClassSymbol.java
+++ b/java/com/google/turbine/binder/sym/ClassSymbol.java
@@ -17,7 +17,7 @@
 package com.google.turbine.binder.sym;
 
 import com.google.errorprone.annotations.Immutable;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A class symbol.
diff --git a/java/com/google/turbine/binder/sym/FieldSymbol.java b/java/com/google/turbine/binder/sym/FieldSymbol.java
index 0b28209..1040500 100644
--- a/java/com/google/turbine/binder/sym/FieldSymbol.java
+++ b/java/com/google/turbine/binder/sym/FieldSymbol.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.sym;
 
 import com.google.errorprone.annotations.Immutable;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A field symbol. */
 @Immutable
diff --git a/java/com/google/turbine/binder/sym/MethodSymbol.java b/java/com/google/turbine/binder/sym/MethodSymbol.java
index 3aa0481..12c1aa5 100644
--- a/java/com/google/turbine/binder/sym/MethodSymbol.java
+++ b/java/com/google/turbine/binder/sym/MethodSymbol.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.sym;
 
 import com.google.errorprone.annotations.Immutable;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A method symbol. */
 @Immutable
diff --git a/java/com/google/turbine/binder/sym/ModuleSymbol.java b/java/com/google/turbine/binder/sym/ModuleSymbol.java
index ea3abce..4ce5c7a 100644
--- a/java/com/google/turbine/binder/sym/ModuleSymbol.java
+++ b/java/com/google/turbine/binder/sym/ModuleSymbol.java
@@ -17,7 +17,7 @@
 package com.google.turbine.binder.sym;
 
 import com.google.errorprone.annotations.Immutable;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A module symbol. */
 @Immutable
diff --git a/java/com/google/turbine/binder/sym/PackageSymbol.java b/java/com/google/turbine/binder/sym/PackageSymbol.java
index 978371d..be071e0 100644
--- a/java/com/google/turbine/binder/sym/PackageSymbol.java
+++ b/java/com/google/turbine/binder/sym/PackageSymbol.java
@@ -17,7 +17,7 @@
 package com.google.turbine.binder.sym;
 
 import com.google.errorprone.annotations.Immutable;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A package symbol. */
 @Immutable
diff --git a/java/com/google/turbine/binder/sym/ParamSymbol.java b/java/com/google/turbine/binder/sym/ParamSymbol.java
index 3fabe32..e939223 100644
--- a/java/com/google/turbine/binder/sym/ParamSymbol.java
+++ b/java/com/google/turbine/binder/sym/ParamSymbol.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.sym;
 
 import com.google.errorprone.annotations.Immutable;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A parameter symbol. */
 @Immutable
diff --git a/java/com/google/turbine/binder/sym/TyVarSymbol.java b/java/com/google/turbine/binder/sym/TyVarSymbol.java
index 27387b7..5ba0788 100644
--- a/java/com/google/turbine/binder/sym/TyVarSymbol.java
+++ b/java/com/google/turbine/binder/sym/TyVarSymbol.java
@@ -18,7 +18,7 @@ package com.google.turbine.binder.sym;
 
 import com.google.errorprone.annotations.Immutable;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A type variable symbol. */
 @Immutable
diff --git a/java/com/google/turbine/binder/sym/package-info.java b/java/com/google/turbine/binder/sym/package-info.java
index be153fc..96f3a87 100644
--- a/java/com/google/turbine/binder/sym/package-info.java
+++ b/java/com/google/turbine/binder/sym/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.binder.sym;
diff --git a/java/com/google/turbine/bytecode/ClassFile.java b/java/com/google/turbine/bytecode/ClassFile.java
index 141c145..2d79341 100644
--- a/java/com/google/turbine/bytecode/ClassFile.java
+++ b/java/com/google/turbine/bytecode/ClassFile.java
@@ -26,7 +26,7 @@ import java.util.ArrayDeque;
 import java.util.Deque;
 import java.util.List;
 import java.util.Map;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A JVMS §4.1 ClassFile. */
 public class ClassFile {
diff --git a/java/com/google/turbine/bytecode/ClassReader.java b/java/com/google/turbine/bytecode/ClassReader.java
index 5022ff7..3510d17 100644
--- a/java/com/google/turbine/bytecode/ClassReader.java
+++ b/java/com/google/turbine/bytecode/ClassReader.java
@@ -39,7 +39,7 @@ import com.google.turbine.model.Const;
 import com.google.turbine.model.TurbineFlag;
 import java.util.ArrayList;
 import java.util.List;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A JVMS §4 class file reader. */
 public class ClassReader {
diff --git a/java/com/google/turbine/bytecode/package-info.java b/java/com/google/turbine/bytecode/package-info.java
index 03c1664..3f0bb60 100644
--- a/java/com/google/turbine/bytecode/package-info.java
+++ b/java/com/google/turbine/bytecode/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.bytecode;
diff --git a/java/com/google/turbine/bytecode/sig/Sig.java b/java/com/google/turbine/bytecode/sig/Sig.java
index 2e4f154..99d98cf 100644
--- a/java/com/google/turbine/bytecode/sig/Sig.java
+++ b/java/com/google/turbine/bytecode/sig/Sig.java
@@ -18,7 +18,7 @@ package com.google.turbine.bytecode.sig;
 
 import com.google.common.collect.ImmutableList;
 import com.google.turbine.model.TurbineConstantTypeKind;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** JVMS 4.7.9.1 signatures. */
 public final class Sig {
diff --git a/java/com/google/turbine/bytecode/sig/package-info.java b/java/com/google/turbine/bytecode/sig/package-info.java
index 9b109a3..c5f449e 100644
--- a/java/com/google/turbine/bytecode/sig/package-info.java
+++ b/java/com/google/turbine/bytecode/sig/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.bytecode.sig;
diff --git a/java/com/google/turbine/deps/Transitive.java b/java/com/google/turbine/deps/Transitive.java
index 75d23f6..673c372 100644
--- a/java/com/google/turbine/deps/Transitive.java
+++ b/java/com/google/turbine/deps/Transitive.java
@@ -33,7 +33,7 @@ import com.google.turbine.bytecode.ClassWriter;
 import com.google.turbine.model.TurbineFlag;
 import java.util.LinkedHashSet;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * Collects the minimal compile-time API for symbols in the supertype closure of compiled classes.
diff --git a/java/com/google/turbine/diag/SourceFile.java b/java/com/google/turbine/diag/SourceFile.java
index ebc0f58..a7c3245 100644
--- a/java/com/google/turbine/diag/SourceFile.java
+++ b/java/com/google/turbine/diag/SourceFile.java
@@ -19,7 +19,7 @@ package com.google.turbine.diag;
 import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A source file. */
 public class SourceFile {
diff --git a/java/com/google/turbine/diag/TurbineDiagnostic.java b/java/com/google/turbine/diag/TurbineDiagnostic.java
index a38c98f..1457868 100644
--- a/java/com/google/turbine/diag/TurbineDiagnostic.java
+++ b/java/com/google/turbine/diag/TurbineDiagnostic.java
@@ -27,7 +27,7 @@ import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.diag.TurbineError.ErrorKind;
 import java.util.Objects;
 import javax.tools.Diagnostic;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A compilation error. */
 public class TurbineDiagnostic {
diff --git a/java/com/google/turbine/lower/Lower.java b/java/com/google/turbine/lower/Lower.java
index fa81d1d..0000ff6 100644
--- a/java/com/google/turbine/lower/Lower.java
+++ b/java/com/google/turbine/lower/Lower.java
@@ -84,7 +84,7 @@ import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Lowering from bound classes to bytecode. */
 public class Lower {
diff --git a/java/com/google/turbine/lower/LowerSignature.java b/java/com/google/turbine/lower/LowerSignature.java
index de20f63..5dffbf8 100644
--- a/java/com/google/turbine/lower/LowerSignature.java
+++ b/java/com/google/turbine/lower/LowerSignature.java
@@ -46,7 +46,7 @@ import java.util.Iterator;
 import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Translator from {@link Type}s to {@link Sig}natures. */
 public class LowerSignature {
diff --git a/java/com/google/turbine/model/Const.java b/java/com/google/turbine/model/Const.java
index 2916b07..bd90f59 100644
--- a/java/com/google/turbine/model/Const.java
+++ b/java/com/google/turbine/model/Const.java
@@ -21,7 +21,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.escape.SourceCodeEscapers;
 import javax.lang.model.element.AnnotationValue;
 import javax.lang.model.element.AnnotationValueVisitor;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * Compile-time constant expressions, including literals of primitive or String type, class
diff --git a/java/com/google/turbine/options/TurbineOptions.java b/java/com/google/turbine/options/TurbineOptions.java
index c104c54..a865371 100644
--- a/java/com/google/turbine/options/TurbineOptions.java
+++ b/java/com/google/turbine/options/TurbineOptions.java
@@ -20,7 +20,7 @@ import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import java.util.Optional;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Header compilation options. */
 @AutoValue
diff --git a/java/com/google/turbine/options/package-info.java b/java/com/google/turbine/options/package-info.java
index 9c12bf8..45bad5e 100644
--- a/java/com/google/turbine/options/package-info.java
+++ b/java/com/google/turbine/options/package-info.java
@@ -14,4 +14,5 @@
  * limitations under the License.
  */
 
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.options;
diff --git a/java/com/google/turbine/parse/ConstExpressionParser.java b/java/com/google/turbine/parse/ConstExpressionParser.java
index 84bbf1d..bfdd8a1 100644
--- a/java/com/google/turbine/parse/ConstExpressionParser.java
+++ b/java/com/google/turbine/parse/ConstExpressionParser.java
@@ -32,7 +32,7 @@ import com.google.turbine.tree.Tree.Expression;
 import com.google.turbine.tree.Tree.Ident;
 import com.google.turbine.tree.TurbineOperatorKind;
 import java.util.Optional;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A parser for compile-time constant expressions. */
 public class ConstExpressionParser {
diff --git a/java/com/google/turbine/parse/Parser.java b/java/com/google/turbine/parse/Parser.java
index 77457b7..c26900f 100644
--- a/java/com/google/turbine/parse/Parser.java
+++ b/java/com/google/turbine/parse/Parser.java
@@ -63,7 +63,7 @@ import java.util.Deque;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Optional;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * A parser for the subset of Java required for header compilation.
diff --git a/java/com/google/turbine/parse/StreamLexer.java b/java/com/google/turbine/parse/StreamLexer.java
index cc51002..b9f9c5c 100644
--- a/java/com/google/turbine/parse/StreamLexer.java
+++ b/java/com/google/turbine/parse/StreamLexer.java
@@ -22,7 +22,7 @@ import static com.google.turbine.parse.UnicodeEscapePreprocessor.ASCII_SUB;
 import com.google.turbine.diag.SourceFile;
 import com.google.turbine.diag.TurbineError;
 import com.google.turbine.diag.TurbineError.ErrorKind;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link Lexer} that streams input from a {@link UnicodeEscapePreprocessor}. */
 public class StreamLexer implements Lexer {
diff --git a/java/com/google/turbine/processing/TurbineAnnotationMirror.java b/java/com/google/turbine/processing/TurbineAnnotationMirror.java
index a4779a4..010fa6c 100644
--- a/java/com/google/turbine/processing/TurbineAnnotationMirror.java
+++ b/java/com/google/turbine/processing/TurbineAnnotationMirror.java
@@ -45,7 +45,7 @@ import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.ErrorType;
 import javax.lang.model.type.TypeMirror;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * An implementation of {@link AnnotationMirror} and {@link AnnotationValue} backed by {@link
diff --git a/java/com/google/turbine/processing/TurbineElement.java b/java/com/google/turbine/processing/TurbineElement.java
index 1b33a99..fff27b7 100644
--- a/java/com/google/turbine/processing/TurbineElement.java
+++ b/java/com/google/turbine/processing/TurbineElement.java
@@ -79,7 +79,7 @@ import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.TypeParameterElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.TypeMirror;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An {@link Element} implementation backed by a {@link Symbol}. */
 @SuppressWarnings("nullness") // TODO(cushon): Address nullness diagnostics.
diff --git a/java/com/google/turbine/processing/TurbineMessager.java b/java/com/google/turbine/processing/TurbineMessager.java
index 9c333b2..37d6b18 100644
--- a/java/com/google/turbine/processing/TurbineMessager.java
+++ b/java/com/google/turbine/processing/TurbineMessager.java
@@ -42,7 +42,7 @@ import javax.lang.model.element.AnnotationMirror;
 import javax.lang.model.element.AnnotationValue;
 import javax.lang.model.element.Element;
 import javax.tools.Diagnostic;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Turbine's implementation of {@link Messager}. */
 public class TurbineMessager implements Messager {
diff --git a/java/com/google/turbine/processing/TurbineName.java b/java/com/google/turbine/processing/TurbineName.java
index a9ebe7c..5232491 100644
--- a/java/com/google/turbine/processing/TurbineName.java
+++ b/java/com/google/turbine/processing/TurbineName.java
@@ -19,7 +19,7 @@ package com.google.turbine.processing;
 import static java.util.Objects.requireNonNull;
 
 import javax.lang.model.element.Name;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An implementation of {@link Name} backed by a {@link CharSequence}. */
 public class TurbineName implements Name {
diff --git a/java/com/google/turbine/processing/TurbineProcessingEnvironment.java b/java/com/google/turbine/processing/TurbineProcessingEnvironment.java
index 8b44e75..4f32033 100644
--- a/java/com/google/turbine/processing/TurbineProcessingEnvironment.java
+++ b/java/com/google/turbine/processing/TurbineProcessingEnvironment.java
@@ -24,7 +24,7 @@ import javax.annotation.processing.ProcessingEnvironment;
 import javax.lang.model.SourceVersion;
 import javax.lang.model.util.Elements;
 import javax.lang.model.util.Types;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** Turbine's {@link ProcessingEnvironment}. */
 public class TurbineProcessingEnvironment implements ProcessingEnvironment {
diff --git a/java/com/google/turbine/processing/TurbineTypeMirror.java b/java/com/google/turbine/processing/TurbineTypeMirror.java
index 690f7fc..4cd8ba1 100644
--- a/java/com/google/turbine/processing/TurbineTypeMirror.java
+++ b/java/com/google/turbine/processing/TurbineTypeMirror.java
@@ -58,7 +58,7 @@ import javax.lang.model.type.TypeMirror;
 import javax.lang.model.type.TypeVariable;
 import javax.lang.model.type.TypeVisitor;
 import javax.lang.model.type.WildcardType;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A {@link TypeMirror} implementation backed by a {@link Type}. */
 public abstract class TurbineTypeMirror implements TypeMirror {
diff --git a/java/com/google/turbine/processing/TurbineTypes.java b/java/com/google/turbine/processing/TurbineTypes.java
index 8a70abe..32e1a99 100644
--- a/java/com/google/turbine/processing/TurbineTypes.java
+++ b/java/com/google/turbine/processing/TurbineTypes.java
@@ -68,7 +68,7 @@ import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.type.WildcardType;
 import javax.lang.model.util.Types;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An implementation of {@link Types} backed by turbine's {@link TypeMirror}. */
 @SuppressWarnings("nullness") // TODO(cushon): Address nullness diagnostics.
diff --git a/java/com/google/turbine/tree/Pretty.java b/java/com/google/turbine/tree/Pretty.java
index 211774f..6838530 100644
--- a/java/com/google/turbine/tree/Pretty.java
+++ b/java/com/google/turbine/tree/Pretty.java
@@ -34,7 +34,7 @@ import com.google.turbine.tree.Tree.ModUses;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** A pretty-printer for {@link Tree}s. */
 public class Pretty implements Tree.Visitor<@Nullable Void, @Nullable Void> {
diff --git a/java/com/google/turbine/tree/Tree.java b/java/com/google/turbine/tree/Tree.java
index 88477a1..7d04312 100644
--- a/java/com/google/turbine/tree/Tree.java
+++ b/java/com/google/turbine/tree/Tree.java
@@ -29,7 +29,7 @@ import java.util.ArrayDeque;
 import java.util.Deque;
 import java.util.Optional;
 import java.util.Set;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An AST node. */
 public abstract class Tree {
diff --git a/java/com/google/turbine/tree/package-info.java b/java/com/google/turbine/tree/package-info.java
index e400f40..2803c67 100644
--- a/java/com/google/turbine/tree/package-info.java
+++ b/java/com/google/turbine/tree/package-info.java
@@ -15,4 +15,5 @@
  */
 
 @com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.nullness.NullMarked
 package com.google.turbine.tree;
diff --git a/java/com/google/turbine/type/AnnoInfo.java b/java/com/google/turbine/type/AnnoInfo.java
index 77ea2a5..d42af5c 100644
--- a/java/com/google/turbine/type/AnnoInfo.java
+++ b/java/com/google/turbine/type/AnnoInfo.java
@@ -29,7 +29,7 @@ import com.google.turbine.tree.Tree.Anno;
 import com.google.turbine.tree.Tree.Expression;
 import java.util.Map;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** An annotation use. */
 public class AnnoInfo {
diff --git a/java/com/google/turbine/type/Type.java b/java/com/google/turbine/type/Type.java
index d6269b3..5e46f88 100644
--- a/java/com/google/turbine/type/Type.java
+++ b/java/com/google/turbine/type/Type.java
@@ -32,7 +32,7 @@ import com.google.turbine.tree.Tree;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /** JLS 4 types. */
 public interface Type {
diff --git a/java/com/google/turbine/types/Canonicalize.java b/java/com/google/turbine/types/Canonicalize.java
index e0e9e00..a0ba2c4 100644
--- a/java/com/google/turbine/types/Canonicalize.java
+++ b/java/com/google/turbine/types/Canonicalize.java
@@ -46,7 +46,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.nullness.Nullable;
 
 /**
  * Canonicalizes qualified type names so qualifiers are always the declaring class of the qualified