apache · vlsi · Aug 23, 2026 · Aug 23, 2026 · Aug 23, 2026 · Aug 23, 2026
diff --git a/.editorconfig b/.editorconfig
@@ -20,9 +20,6 @@ ij_java_use_single_class_imports = true
 max_line_length = 100
 ij_any_wrap_long_lines = true
 
-[*.astub]
-indent_size = 2
-
 [*.java]
 # Doc: https://youtrack.jetbrains.com/issue/IDEA-170643#focus=streamItem-27-3708697.0-0
 # $ means "static"

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
@@ -343,16 +343,19 @@ jobs:
 
   errorprone-guava-latest:
     if: github.event.action != 'labeled'
-    name: 'ErrorProne (JDK 11, latest Guava)'
+    # This is the only job that verifies nullness, so a nullability problem fails here alone and
+    # the test jobs keep reporting test failures
+    name: 'ErrorProne and NullAway (JDK 21, latest Guava)'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
         with:
           fetch-depth: 50
-      - name: 'Set up JDK 11'
+      # Error Prone 2.43 and later require JDK 21, and NullAway requires JDK 17
+      - name: 'Set up JDK 21'
         uses: actions/setup-java@v5
         with:
-          java-version: 11
+          java-version: 21
           distribution: 'zulu'
       - uses: burrunan/gradle-cache-action@v1
         name: Test
@@ -362,44 +365,6 @@ jobs:
           # ErrorProne checks for Beta APIs, so use the latest supported Guava version
           arguments: --scan --no-parallel --no-daemon -Pguava.version=${{ env.GUAVA_MAX }} -PenableErrorprone classes
 
-  linux-checkerframework:
-    name: 'CheckerFramework (JDK 11)'
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v5
-        with:
-          fetch-depth: 50
-      - name: 'Set up JDK 11'
-        uses: actions/setup-java@v5
-        with:
-          java-version: 11
-          distribution: 'zulu'
-      - name: 'Run CheckerFramework'
-        uses: burrunan/gradle-cache-action@v1
-        with:
-          job-id: checkerframework-jdk11
-          remote-build-cache-proxy-enabled: false
-          arguments: --scan --no-parallel --no-daemon -PenableCheckerframework :linq4j:classes :core:classes :server:classes
-
-  linux-checkerframework-oldest-guava:
-    name: 'CheckerFramework (JDK 11, oldest Guava)'
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v5
-        with:
-          fetch-depth: 50
-      - name: 'Set up JDK 11'
-        uses: actions/setup-java@v5
-        with:
-          java-version: 11
-          distribution: 'zulu'
-      - name: 'Run CheckerFramework'
-        uses: burrunan/gradle-cache-action@v1
-        with:
-          job-id: checkerframework-jdk11
-          remote-build-cache-proxy-enabled: false
-          arguments: --scan --no-parallel --no-daemon -Pguava.version=${{ env.GUAVA_MIN }} -PenableCheckerframework :linq4j:classes :core:classes :server:classes
-
   linux-slow:
     # Run slow tests when the commit is on main or it is requested explicitly by adding an
     # appropriate label in the PR

diff --git a/.idea/vcs.xml b/.idea/vcs.xml
diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/AbstractArrowEnumerator.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/AbstractArrowEnumerator.java
@@ -28,14 +28,16 @@
 import org.apache.arrow.vector.types.TimeUnit;
 import org.apache.arrow.vector.types.pojo.ArrowType;
 
+import org.jspecify.annotations.Nullable;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
 /**
  * Enumerator that reads from a collection of Arrow value-vectors.
  */
-abstract class AbstractArrowEnumerator implements Enumerator<Object> {
+abstract class AbstractArrowEnumerator implements Enumerator<@Nullable Object> {
   protected final ArrowFileReader arrowFileReader;
   protected final List<Integer> fields;
   protected final List<ValueVector> valueVectors;
@@ -82,11 +84,11 @@ protected boolean loadNextNonEmptyArrowBatch() {
     }
   }
 
-  @Override public Object current() {
+  @Override public @Nullable Object current() {
     if (fields.size() == 1) {
       return getValue(this.valueVectors.get(0), currRowIndex);
     }
-    Object[] current = new Object[valueVectors.size()];
+    final @Nullable Object[] current = new Object[valueVectors.size()];
     for (int i = 0; i < valueVectors.size(); i++) {
       ValueVector vector = this.valueVectors.get(i);
       current[i] = getValue(vector, currRowIndex);
@@ -99,7 +101,7 @@ protected boolean loadNextNonEmptyArrowBatch() {
    * <p>For {@link TimeStampVector}, converts the raw value to
    * milliseconds since epoch, which is the representation used by
    * Calcite's Enumerable runtime for TIMESTAMP types. */
-  protected static Object getValue(ValueVector vector, int index) {
+  protected static @Nullable Object getValue(ValueVector vector, int index) {
     if (vector instanceof TimeStampVector) {
       if (vector.isNull(index)) {
         return null;

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowEnumerable.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowEnumerable.java
@@ -24,12 +24,14 @@
 import org.apache.arrow.vector.ipc.ArrowFileReader;
 import org.apache.arrow.vector.types.pojo.Schema;
 
+import org.jspecify.annotations.Nullable;
+
 import java.util.List;
 
 /**
  * Enumerable that reads from Arrow value-vectors.
  */
-class ArrowEnumerable extends AbstractEnumerable<Object> {
+class ArrowEnumerable extends AbstractEnumerable<@Nullable Object> {
   private final ArrowFileReader arrowFileReader;
   private final ImmutableIntList fields;
   private final List<List<List<String>>> conditions;
@@ -45,7 +47,7 @@ class ArrowEnumerable extends AbstractEnumerable<Object> {
     this.onClose = onClose;
   }
 
-  @Override public Enumerator<Object> enumerator() {
+  @Override public Enumerator<@Nullable Object> enumerator() {
     try {
       if (!conditions.isEmpty()) {
         return new ArrowFilterEnumerator(arrowFileReader, fields,

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowProject.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowProject.java
@@ -30,7 +30,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowRel.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowRel.java
@@ -21,7 +21,7 @@
 import org.apache.calcite.rel.RelNode;
 import org.apache.calcite.util.ImmutableIntList;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -32,14 +32,14 @@
 * Relational expression that uses the Arrow calling convention.
 */
 public interface ArrowRel extends RelNode {
  void implement(Implementor implementor);

  /** Calling convention for relational operations that occur in Arrow. */
  Convention CONVENTION = new Convention.Impl("ARROW", ArrowRel.class);

  /** Callback for the implementation process that converts a tree of
   * {@link ArrowRel} nodes into a SQL query. */
  class Implementor {
    @Nullable List<Integer> selectFields;
    final List<List<ConditionToken>> whereClause = new ArrayList<>();
    @Nullable RelOptTable table;
@@ -70,7 +70,7 @@
      selectFields = ImmutableIntList.copyOf(fields);
    }

    public void visitInput(int ordinal, RelNode input) {
      checkArgument(ordinal == 0);
      ((ArrowRel) input).implement(this);
    }

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowRules.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowRules.java
@@ -35,8 +35,8 @@
 
 import com.google.common.collect.ImmutableList;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
 import org.immutables.value.Value;
+import org.jspecify.annotations.Nullable;
 
 import java.util.List;
 
@@ -49,14 +49,14 @@
  public static final ArrowProjectRule PROJECT_SCAN =
      ArrowProjectRule.DEFAULT_CONFIG.toRule(ArrowProjectRule.class);

  public static final ArrowFilterRule FILTER_SCAN =
      ArrowFilterRule.Config.DEFAULT.toRule();

  public static final ConverterRule TO_ENUMERABLE =
      ArrowToEnumerableConverterRule.DEFAULT_CONFIG
          .toRule(ArrowToEnumerableConverterRule.class);

  public static final List<RelOptRule> RULES = ImmutableList.of(PROJECT_SCAN, FILTER_SCAN);

  static List<String> arrowFieldNames(final RelDataType rowType) {
    return SqlValidatorUtil.uniquify(rowType.getFieldNames(),
@@ -177,7 +177,7 @@
    }

    @Override public RelNode convert(RelNode rel) {
      RelTraitSet newTraitSet = rel.getTraitSet().replace(getOutConvention());
      return new ArrowToEnumerableConverter(rel.getCluster(), newTraitSet, rel);
    }
  }

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowSchema.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowSchema.java
@@ -29,7 +29,7 @@
 import com.google.common.base.Suppliers;
 import com.google.common.collect.ImmutableMap;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowTable.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowTable.java
@@ -44,16 +44,14 @@
 import org.apache.arrow.vector.types.pojo.Field;
 import org.apache.arrow.vector.types.pojo.Schema;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.lang.reflect.Type;
 import java.util.List;
 
-import static java.util.Objects.requireNonNull;
-
 /**
  * Table backed by an Apache Arrow file.
  *
@@ -100,9 +98,8 @@ public class ArrowTable extends AbstractTable
   /** Called via code generation; see uses of
    * {@link org.apache.calcite.adapter.arrow.ArrowMethod#ARROW_QUERY}. */
   @SuppressWarnings("unused")
-  public Enumerable<Object> query(DataContext root, ImmutableIntList fields,
-      List<List<List<String>>> conditions) {
-    requireNonNull(fields, "fields");
+  public Enumerable<@Nullable Object> query(@Nullable DataContext root,
+      ImmutableIntList fields, List<List<List<String>>> conditions) {
 
     FileInputStream fis = null;
     try {
@@ -188,7 +185,7 @@ private ArrowTable getTable() {
      * @return result as enumerable
      */
     @SuppressWarnings("UnusedDeclaration")
-    public Enumerable<Object> query(List<Integer> fields,
+    public Enumerable<@Nullable Object> query(List<Integer> fields,
         List<List<List<String>>> conditions) {
       final ImmutableIntList fieldList = ImmutableIntList.copyOf(fields);
       return getTable().query(null, fieldList, conditions);

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowTranslator.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ArrowTranslator.java
@@ -29,7 +29,7 @@
 import org.apache.calcite.sql.type.SqlTypeName;
 import org.apache.calcite.util.DateString;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/ConditionToken.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/ConditionToken.java
@@ -18,7 +18,7 @@
 
 import com.google.common.collect.ImmutableList;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 import java.util.List;
 

diff --git a/arrow/src/main/java/org/apache/calcite/adapter/arrow/package-info.java b/arrow/src/main/java/org/apache/calcite/adapter/arrow/package-info.java
@@ -18,4 +18,7 @@
 /**
  * Query provider that reads from Arrow files.
  */
+@NullMarked
 package org.apache.calcite.adapter.arrow;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/babel/src/main/java/org/apache/calcite/sql/babel/SqlBabelCreateTable.java b/babel/src/main/java/org/apache/calcite/sql/babel/SqlBabelCreateTable.java
@@ -28,7 +28,7 @@
 import org.apache.calcite.sql.parser.SqlParserPos;
 import org.apache.calcite.util.ImmutableNullableList;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 
 import java.util.List;
 
@@ -44,7 +44,9 @@ public class SqlBabelCreateTable extends SqlCreateTable {
           (operator, functionQualifier, pos, operands) ->
               new SqlBabelCreateTable(pos,
                   requireNonNull((SqlLiteral) operands[0]).booleanValue(),
-                  requireNonNull((SqlLiteral) operands[1]).symbolValue(TableCollectionType.class),
+                  requireNonNull(
+                      requireNonNull((SqlLiteral) operands[1])
+                          .symbolValue(TableCollectionType.class)),
                   requireNonNull((SqlLiteral) operands[2]).booleanValue(),
                   requireNonNull((SqlLiteral) operands[3]).booleanValue(),
                   (SqlIdentifier) requireNonNull(operands[4]),
@@ -65,7 +67,7 @@ public SqlBabelCreateTable(SqlParserPos pos, boolean replace,
     this.volatile_ = volatile_;
   }
 
-  @SuppressWarnings("nullness")
+  @SuppressWarnings("NullAway")
   @Override public List<SqlNode> getOperandList() {
     return ImmutableNullableList.of(SqlLiteral.createBoolean(getReplace(), pos),
         SqlLiteral.createSymbol(tableCollectionType, pos),

diff --git a/babel/src/main/java/org/apache/calcite/sql/babel/package-info.java b/babel/src/main/java/org/apache/calcite/sql/babel/package-info.java
@@ -18,4 +18,7 @@
 /**
  * Parse tree for SQL extensions used by the Babel parser.
  */
+@NullMarked
 package org.apache.calcite.sql.babel;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/babel/src/main/java/org/apache/calcite/sql/babel/postgres/package-info.java b/babel/src/main/java/org/apache/calcite/sql/babel/postgres/package-info.java
@@ -18,4 +18,7 @@
 /**
  * Parse tree for PostgreSQL extensions used by the Babel parser.
  */
+@NullMarked
 package org.apache.calcite.sql.babel.postgres;
+
+import org.jspecify.annotations.NullMarked;
diff --git a/babel/src/test/java/org/apache/calcite/test/BabelParserTest.java b/babel/src/test/java/org/apache/calcite/test/BabelParserTest.java
@@ -34,7 +34,7 @@
 
 import com.google.common.base.Throwables;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 

diff --git a/babel/src/test/java/org/apache/calcite/test/BabelQuidemTest.java b/babel/src/test/java/org/apache/calcite/test/BabelQuidemTest.java
@@ -30,7 +30,7 @@
 import net.hydromatic.quidem.CommandHandler;
 import net.hydromatic.quidem.Quidem;
 
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.BeforeEach;
 
 import java.sql.Connection;

diff --git a/babel/src/test/java/org/apache/calcite/test/package-info.java b/babel/src/test/java/org/apache/calcite/test/package-info.java
@@ -18,11 +18,4 @@
 /**
  * Tests for Calcite.
  */
-@DefaultQualifier(value = NonNull.class, locations = TypeUseLocation.FIELD)
-@DefaultQualifier(value = NonNull.class, locations = TypeUseLocation.PARAMETER)
-@DefaultQualifier(value = NonNull.class, locations = TypeUseLocation.RETURN)
 package org.apache.calcite.test;
-
-import org.checkerframework.checker.nullness.qual.NonNull;
-import org.checkerframework.framework.qual.DefaultQualifier;
-import org.checkerframework.framework.qual.TypeUseLocation;
diff --git a/bom/build.gradle.kts b/bom/build.gradle.kts
@@ -71,7 +71,6 @@ dependencies {
         apiv("com.yahoo.datasketches:sketches-core")
         apiv("commons-codec:commons-codec")
         apiv("commons-io:commons-io")
-        apiv("org.checkerframework:checker-qual", "checkerframework")
         apiv("org.locationtech.jts:jts-core")
         apiv("org.locationtech.jts.io:jts-io-common")
         apiv("org.locationtech.proj4j:proj4j")
@@ -148,6 +147,7 @@ dependencies {
         apiv("org.incava:java-diff")
         apiv("org.jboss:jandex")
         apiv("org.jooq:joou-java-6", "joou")
+        apiv("org.jspecify:jspecify")
         apiv("org.jsoup:jsoup")
         apiv("org.junit:junit-bom", "junit5")
         apiv("org.mockito:mockito-core", "mockito")