fix: unwrap lambda deserialization cause (#136)

Base on the JDK version, SerializedLambda.readResolve may differently wrap
the cause of error.
This change analyzes the exception to unwrap the root cause of the failure,
allowing the debug tool to provide the trace of potential unserializable
lambda candidates.

References #135

kubernetes-kit-starter/src/main/java/com/vaadin/kubernetes/starter/sessiontracker/serialization/debug/Job.java

@@ -9,8 +9,10 @@
  */
 package com.vaadin.kubernetes.starter.sessiontracker.serialization.debug;
 
+import java.io.InvalidObjectException;
 import java.io.ObjectStreamClass;
 import java.lang.invoke.SerializedLambda;
+import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -194,10 +196,11 @@ void deserializationFailed(Exception ex) {
         outcome.add(Outcome.DESERIALIZATION_FAILED);
         log(CATEGORY_ERRORS,
                 Outcome.DESERIALIZATION_FAILED.name() + ": " + ex.getMessage());
-        if (ex instanceof ClassCastException
-                && ex.getMessage().contains(SerializedLambda.class.getName())
+        Throwable cause = tryUnwrapLambdaDeserializationCause(ex);
+        if (cause instanceof ClassCastException
+                && cause.getMessage().contains(SerializedLambda.class.getName())
                 && !serializedLambdaMap.isEmpty()) {
-            String targetType = tryDetectClassCastTarget(ex.getMessage());
+            String targetType = tryDetectClassCastTarget(cause.getMessage());
             if (targetType != null) {
                 String bestCandidates = serializedLambdaMap.values().stream()
                         .filter(serializedLambda -> serializedLambda
@@ -223,6 +226,19 @@ void deserializationFailed(Exception ex) {
         }
     }
 
+    // Base on the JDK version, SerializedLambda.readResolve may differently
+    // wrap the cause of error
+    private Throwable tryUnwrapLambdaDeserializationCause(Throwable exception) {
+        Throwable cause = exception;
+        if (cause instanceof InvalidObjectException) {
+            cause = cause.getCause();
+        }
+        if (cause instanceof InvocationTargetException) {
+            cause = cause.getCause();
+        }
+        return cause;
+    }
+
     private Logger getLogger() {
         return LoggerFactory.getLogger(DebugMode.class);
     }

kubernetes-kit-starter/src/test/java/com/vaadin/kubernetes/starter/sessiontracker/serialization/debug/SerializationDebugRequestHandlerTest.java

@@ -1,21 +1,23 @@
 package com.vaadin.kubernetes.starter.sessiontracker.serialization.debug;
 
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpSession;
+
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
+import java.lang.invoke.SerializedLambda;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Stream;
 
-import jakarta.servlet.http.HttpServletRequest;
-import jakarta.servlet.http.HttpSession;
 import org.assertj.core.api.SoftAssertions;
 import org.assertj.core.data.Index;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
 import org.springframework.mock.web.MockHttpSession;
@@ -314,8 +316,40 @@ void handleRequest_serializationTimeout_timeoutReported() {
     }
 
     @Test
-    @Disabled("Find a way to simulate SerializedLambda ClassCastException")
     void handleRequest_lambdaSelfReferenceClassCast_errorCaught() {
+
+        LambdaDeserializationClassCast holder = new LambdaDeserializationClassCast();
+        httpSession.setAttribute("OBJ1", holder.selfReferenceLambda);
+
+        runDebugTool();
+        Result result = resultHolder.get();
+        assertThat(result.getOutcomes())
+                .containsExactly(Outcome.DESERIALIZATION_FAILED);
+        String unserializableInfo = String.join(System.lineSeparator(),
+                result.getErrors());
+        assertThat(unserializableInfo)
+                .contains("cannot assign instance of "
+                        + SerializedLambda.class.getName())
+                .contains("field "
+                        + LambdaDeserializationClassCast.class.getName()
+                        + ".selfReferenceLambda")
+                .contains("in instance of "
+                        + LambdaDeserializationClassCast.class.getName())
+                .contains(
+                        "SERIALIZED LAMBDA CLASS CAST EXCEPTION BEST CANDIDATES")
+                .contains("SerializedLambda[capturingClass=class "
+                        + LambdaDeserializationClassCast.class.getName());
+    }
+
+    static class LambdaDeserializationClassCast implements Serializable {
+
+        private final Serializable capture = new Serializable() {
+        };
+
+        private final SerializableRunnable selfReferenceLambda = () -> {
+            Objects.requireNonNull(capture);
+        };
+
     }
 
     private void assertDebugToolNotExecuted() {