[api] Do not ask an immutable partitionOptions list whether it contains null

paimon-api/src/main/java/org/apache/paimon/rest/requests/CreatePartitionsRequest.java

@@ -32,6 +32,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 import static org.apache.paimon.utils.Preconditions.checkArgument;
 
@@ -106,7 +107,7 @@ public CreatePartitionsRequest(
                                 && partitionOptions.size() == partitionSpecs.size()),
                 "partitionOptions must be null or have the same size as partitionSpecs.");
         checkArgument(
-                partitionOptions == null || !partitionOptions.contains(null),
+                partitionOptions == null || partitionOptions.stream().noneMatch(Objects::isNull),
                 "partitionOptions must not contain null maps.");
         checkArgument(
                 partitionOptions == null

paimon-core/src/test/java/org/apache/paimon/rest/RESTApiJsonTest.java

@@ -65,6 +65,7 @@
 
 import org.junit.Test;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
@@ -530,6 +531,29 @@
         assertFalse(PartitionStatistics.isKnown(parsedUnknown.fileCount()));
     }
 
+    @Test
+    public void createPartitionsRequestAcceptsImmutablePartitionOptionsTest() {
+        Map<String, String> spec = Collections.singletonMap("dt", "20260916");
+        Map<String, String> options =
+                Collections.singletonMap("path", "oss://bucket/archive/dt=20260916");
+
+        // List.of answers contains(null) with a NullPointerException rather than false, so a
+        // caller handing over a valid immutable list must not be asked that question.
+        CreatePartitionsRequest request =
+                new CreatePartitionsRequest(List.of(spec), true, null, null, List.of(options));
+        assertEquals(List.of(options), request.getPartitionOptions());
+
+        List<Map<String, String>> withNullEntry = new ArrayList<>();
+        withNullEntry.add(null);
+        IllegalArgumentException failure =
+                assertThrows(
+                        IllegalArgumentException.class,
+                        () ->
+                                new CreatePartitionsRequest(
+                                        List.of(spec), true, null, null, withNullEntry));
+        assertTrue(failure.getMessage().contains("partitionOptions must not contain null maps"));
+    }
+
     @Test
     public void dropPartitionsResponseParseTest() throws Exception {
         Map<String, String> dropped = new HashMap<>();