Implement getErrorClass explicitly to avoid AbstractMethodError on Spark builds without the deprecated default

src/main/scala/org/apache/spark/sql/pulsar/PulsarExceptions.scala

@@ -104,6 +104,13 @@ private[pulsar] class PulsarIllegalStateException(
   override def getMessageParameters: java.util.Map[String, String] = messageParameters.asJava
 
   override def getCondition: String = errorClass
+
+  // Some Spark distributions (notably Databricks Runtime) leave the deprecated
+  // SparkThrowable.getErrorClass abstract instead of defaulting to getCondition.
+  // Implement it explicitly so a thrown exception can be surfaced by Spark's
+  // TaskResultGetter instead of raising AbstractMethodError (which silently hangs
+  // the job). Harmless on OSS Spark, where it overrides the deprecated default.
+  override def getErrorClass: String = errorClass
 }
 
 
@@ -125,4 +132,8 @@ private[pulsar] class PulsarIllegalArgumentException(
   override def getMessageParameters: java.util.Map[String, String] = messageParameters.asJava
 
   override def getCondition: String = errorClass
+
+  // See PulsarIllegalStateException above: explicit override guards against Spark
+  // builds (e.g. Databricks Runtime) that leave SparkThrowable.getErrorClass abstract.
+  override def getErrorClass: String = errorClass
 }

src/test/scala/org/apache/spark/sql/pulsar/PulsarExceptionsSuite.scala

@@ -0,0 +1,42 @@
+/*
+ * Licensed 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.spark.sql.pulsar
+
+import org.apache.spark.SparkFunSuite
+
+class PulsarExceptionsSuite extends SparkFunSuite {
+
+  // Regression guard for AbstractMethodError on Spark distributions that leave the
+  // deprecated SparkThrowable.getErrorClass abstract (e.g. Databricks Runtime). The
+  // connector exceptions must declare their OWN getErrorClass body; relying on the
+  // interface default causes Spark's TaskResultGetter to raise AbstractMethodError
+  // when the exception escapes a task, which silently hangs the job.
+
+  test("PulsarIllegalStateException declares its own getErrorClass") {
+    val e = PulsarExceptions.pulsarSinkIncompatibleSchema(
+      "persistent://public/default/t", new RuntimeException("boom"))
+    assert(e.getCondition === "PULSAR_SINK_INCOMPATIBLE_SCHEMA")
+    // getDeclaredMethod throws NoSuchMethodException if the body is not on the class
+    // itself (i.e. if it falls back to the SparkThrowable default).
+    val method = classOf[PulsarIllegalStateException].getDeclaredMethod("getErrorClass")
+    assert(method.invoke(e) === "PULSAR_SINK_INCOMPATIBLE_SCHEMA")
+  }
+
+  test("PulsarIllegalArgumentException declares its own getErrorClass") {
+    val e = PulsarExceptions.pulsarProviderInvalidSaveMode("Append")
+    assert(e.getCondition === "PULSAR_PROVIDER_INVALID_SAVE_MODE")
+    val method = classOf[PulsarIllegalArgumentException].getDeclaredMethod("getErrorClass")
+    assert(method.invoke(e) === "PULSAR_PROVIDER_INVALID_SAVE_MODE")
+  }
+}