From 5c9c45c45d77e3b609108cc69eac15240db8818b Mon Sep 17 00:00:00 2001
From: dylanhz <53137516+dylanhz@users.noreply.github.com>
Date: Mon, 16 Dec 2024 22:23:48 +0800
Subject: [PATCH] [FLINK-35887][core] Fix NPE in TypeExtractor where
 getSuperclass from an interface returns null

This closes #25801
---
 .../api/java/typeutils/TypeExtractor.java     |  4 +++-
 .../apache/flink/types/PojoTestUtilsTest.java | 24 +++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/flink-core/src/main/java/org/apache/flink/api/java/typeutils/TypeExtractor.java b/flink-core/src/main/java/org/apache/flink/api/java/typeutils/TypeExtractor.java
index fd7978d323542..5b4fce8b22150 100644
--- a/flink-core/src/main/java/org/apache/flink/api/java/typeutils/TypeExtractor.java
+++ b/flink-core/src/main/java/org/apache/flink/api/java/typeutils/TypeExtractor.java
@@ -2224,7 +2224,9 @@ protected <OUT, IN1, IN2> TypeInformation<OUT> analyzePojo(
      */
     @PublicEvolving
     public static boolean isRecord(Class<?> clazz) {
-        return clazz.getSuperclass().getName().equals("java.lang.Record")
+        Class<?> superclass = clazz.getSuperclass();
+        return superclass != null
+                && superclass.getName().equals("java.lang.Record")
                 && (clazz.getModifiers() & Modifier.FINAL) != 0;
     }
 
diff --git a/flink-test-utils-parent/flink-test-utils/src/test/java/org/apache/flink/types/PojoTestUtilsTest.java b/flink-test-utils-parent/flink-test-utils/src/test/java/org/apache/flink/types/PojoTestUtilsTest.java
index 6d9f399ea7809..506124816b1da 100644
--- a/flink-test-utils-parent/flink-test-utils/src/test/java/org/apache/flink/types/PojoTestUtilsTest.java
+++ b/flink-test-utils-parent/flink-test-utils/src/test/java/org/apache/flink/types/PojoTestUtilsTest.java
@@ -17,9 +17,17 @@
 
 package org.apache.flink.types;
 
+import org.apache.flink.api.common.typeinfo.TypeInfo;
+import org.apache.flink.api.common.typeinfo.TypeInfoFactory;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeinfo.Types;
+
 import org.junit.jupiter.api.Test;
 
+import java.lang.reflect.Type;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
@@ -41,6 +49,12 @@ void testPojoAcceptedIfKryoRequired() {
         PojoTestUtils.assertSerializedAsPojo(PojoRequiringKryo.class);
     }
 
+    @Test
+    void testPojoTypeInfoOnInterface() {
+        // reported in FLINK-35887
+        PojoTestUtils.assertSerializedAsPojo(Foo.class);
+    }
+
     @Test
     void testWithoutKryoPojoAccepted() {
         PojoTestUtils.assertSerializedAsPojoWithoutKryo(Pojo.class);
@@ -64,4 +78,14 @@ public static class Pojo {
     public static class PojoRequiringKryo {
         public List<Integer> x;
     }
+
+    @TypeInfo(FooFactory.class)
+    public interface Foo {}
+
+    public static class FooFactory extends TypeInfoFactory<Foo> {
+        @Override
+        public TypeInformation<Foo> createTypeInfo(Type type, Map<String, TypeInformation<?>> map) {
+            return Types.POJO(Foo.class, new HashMap<>());
+        }
+    }
 }