fix alter table case fail in RESTCatalogMockServerTest

paimon-core/src/main/java/org/apache/paimon/rest/DefaultErrorHandler.java

@@ -26,6 +26,7 @@
 import org.apache.paimon.rest.exceptions.RESTException;
 import org.apache.paimon.rest.exceptions.ServiceFailureException;
 import org.apache.paimon.rest.exceptions.ServiceUnavailableException;
+import org.apache.paimon.rest.exceptions.UnsupportedOperationException;
 import org.apache.paimon.rest.responses.ErrorResponse;
 
 /** Default error handler. */

paimon-core/src/main/java/org/apache/paimon/rest/RESTCatalog.java

@@ -41,6 +41,7 @@
 import org.apache.paimon.rest.exceptions.BadRequestException;
 import org.apache.paimon.rest.exceptions.ForbiddenException;
 import org.apache.paimon.rest.exceptions.NoSuchResourceException;
+import org.apache.paimon.rest.exceptions.ServiceFailureException;
 import org.apache.paimon.rest.requests.AlterDatabaseRequest;
 import org.apache.paimon.rest.requests.AlterTableRequest;
 import org.apache.paimon.rest.requests.CreateDatabaseRequest;
@@ -367,6 +368,10 @@ public void alterTable(
             throw new ColumnAlreadyExistException(identifier, e.resourceName());
         } catch (ForbiddenException e) {
             throw new TableNoPermissionException(identifier, e);
+        } catch (org.apache.paimon.rest.exceptions.UnsupportedOperationException e) {
+            throw new UnsupportedOperationException(e.getMessage());
+        } catch (ServiceFailureException e) {
+            throw new IllegalStateException(e.getMessage());
         }
     }
 

paimon-core/src/main/java/org/apache/paimon/rest/exceptions/UnsupportedOperationException.java

@@ -0,0 +1,26 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.paimon.rest.exceptions;
+
+/** Exception thrown on HTTP 501 - UnsupportedOperationException. */
+public class UnsupportedOperationException extends RESTException {
+    public UnsupportedOperationException(String message, Object... args) {
+        super(String.format(message, args));
+    }
+}

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

@@ -152,6 +152,12 @@ public MockResponse dispatch(RecordedRequest request) throws InterruptedExceptio
                                 new ErrorResponse(
                                         null, null, e.getCause().getCause().getMessage(), 400);
                         return mockResponse(response, 400);
+                    } else if (e instanceof UnsupportedOperationException) {
+                        response = new ErrorResponse(null, null, e.getMessage(), 501);
+                        return mockResponse(response, 501);
+                    } else if (e instanceof IllegalStateException) {
+                        response = new ErrorResponse(null, null, e.getMessage(), 500);
+                        return mockResponse(response, 500);
                     }
                     return new MockResponse().setResponseCode(500);
                 }
@@ -185,7 +191,7 @@ private static MockResponse databaseApiHandler(
             response = new GetDatabaseResponse(database.name(), database.options());
             return mockResponse(response, 200);
         } else if (request.getMethod().equals("DELETE")) {
-            catalog.dropDatabase(databaseName, true, false);
+            catalog.dropDatabase(databaseName, true, true);
             return new MockResponse().setResponseCode(200);
         }
         return new MockResponse().setResponseCode(404);