fix<data converter>: fail open on exception not found (#1027)

What changed?

Default data converter would throw I/O exception and thus fail workflow processing if the exception no longer exists. This PR changes the behavior by return null instead.

Why?

In V4, thrift exceptions will be removed and thus this is needed to avoid breaking existing workflows.

How did you test it?

Unit Test

Author: shijiesheng

src/main/java/com/uber/cadence/client/ApplicationFailureException.java

@@ -0,0 +1,24 @@
+/**
+ * Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * <p>Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ * <p>Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
+ * except in compliance with the License. A copy of the License is located at
+ *
+ * <p>http://aws.amazon.com/apache2.0
+ *
+ * <p>or in the "license" file accompanying this file. This file 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 com.uber.cadence.client;
+
+import com.uber.cadence.CadenceError;
+
+public final class ApplicationFailureException extends CadenceError {
+
+  public ApplicationFailureException(String message) {
+    super(message);
+  }
+}

src/main/java/com/uber/cadence/converter/CustomThrowableTypeAdapter.java

@@ -22,6 +22,7 @@
 import com.google.gson.reflect.TypeToken;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
+import com.uber.cadence.client.ApplicationFailureException;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
@@ -137,7 +138,7 @@ public T read(JsonReader jsonReader) throws IOException {
       try {
         classType = Class.forName(className);
       } catch (ClassNotFoundException e) {
-        throw new IOException("Cannot deserialize " + className + " exception", e);
+        classType = ApplicationFailureException.class;
       }
       if (!Throwable.class.isAssignableFrom(classType)) {
         throw new IOException("Expected type that extends Throwable: " + className);

src/test/java/com/uber/cadence/converter/JsonDataConverterTest.java

@@ -27,6 +27,7 @@
 import com.uber.cadence.WorkflowExecutionStartedEventAttributes;
 import com.uber.cadence.WorkflowType;
 import com.uber.cadence.activity.Activity;
+import com.uber.cadence.client.ApplicationFailureException;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -270,4 +271,23 @@ public void testException() {
 
     assertEquals("root exception", causeFromConverted.getSuppressed()[0].getMessage());
   }
+
+  @Test
+  public void testExceptionNotFound() {
+    String convertedString =
+        "{\n"
+            + "  \"detailMessage\": \"application exception\",\n"
+            + "  \"stackTrace\": \"com.uber.cadence.converter.JsonDataConverterTest.testExceptionNotFound(JsonDataConverterTest.java:282)\\nsun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\\nsun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)\\nsun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\\njava.lang.reflect.Method.invoke(Method.java:498)\\norg.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)\\norg.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)\\norg.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)\\norg.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)\\norg.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)\\norg.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)\\norg.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)\\norg.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)\\norg.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)\\norg.junit.runners.ParentRunner$4.run(ParentRunner.java:331)\\norg.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)\\norg.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)\\norg.junit.runners.ParentRunner.access$100(ParentRunner.java:66)\\norg.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)\\norg.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)\\norg.junit.runners.ParentRunner.run(ParentRunner.java:413)\\norg.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:93)\\norg.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:40)\\norg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:520)\\norg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:748)\\norg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:443)\\norg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:211)\\n\",\n"
+            + "  \"suppressedExceptions\": [],\n"
+            + "  \"class\": \"com.uber.cadence.converter.ExceptionNotFound\"\n"
+            + "}";
+    RuntimeException fromConverted =
+        converter.fromData(
+            convertedString.getBytes(StandardCharsets.UTF_8),
+            RuntimeException.class,
+            RuntimeException.class);
+    assertEquals(ApplicationFailureException.class, fromConverted.getClass());
+    assertEquals("application exception", fromConverted.getMessage());
+    assertNotSame(fromConverted.getStackTrace().length, 0);
+  }
 }