Same class not assignable. Classloader for same class different

Question

I have spring program for read avro messages from Kafka topic. When message reading occur exception:

org.springframework.messaging.converter.MessageConversionException: Cannot convert from [com.mycompany.myapp.domain.avro.GreetingRecord] to [com.mycompany.myapp.domain.avro.GreetingRecord]

In debug i see that ClassUtils.isAssignable return false for same class:

Class <?> targetClass = parameter.getParameterType();
Class <?> payloadClass = payload.getClass();
if (ClassUtils.isAssignable(targetClass, payloadClass)) { // return false for same class
    this.validate(message, parameter, payload);
    return payload;
} else {
    if (this.converter instanceof SmartMessageConverter) {
        SmartMessageConverter smartConverter = (SmartMessageConverter)this.converter;
        payload = smartConverter.fromMessage(message, targetClass, parameter);
    } else {
        payload = this.converter.fromMessage(message, targetClass);
    }
}

I found that classloaders in targetClass and payloadClass different (RestartClassLoader and Launcher$AppClassLoader)

Target (payload) Class definition:

/**
 * Autogenerated by Avro
 *
 * DO NOT EDIT DIRECTLY
 */
package com.mycompany.myapp.domain.avro;

import org.apache.avro.specific.SpecificData;
import org.apache.avro.message.BinaryMessageEncoder;
import org.apache.avro.message.BinaryMessageDecoder;
import org.apache.avro.message.SchemaStore;

@SuppressWarnings("all")
@org.apache.avro.specific.AvroGenerated
public class GreetingRecord extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
  private static final long serialVersionUID = -39777975679985249L;
  public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"record\",\"name\":\"GreetingRecord\",\"namespace\":\"com.mycompany.myapp.domain.avro\",\"fields\":[{\"name\":\"message\",\"type\":\"string\"}]}");
  public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }

  private static SpecificData MODEL$ = new SpecificData();

  private static final BinaryMessageEncoder<GreetingRecord> ENCODER =
      new BinaryMessageEncoder<GreetingRecord>(MODEL$, SCHEMA$);

  private static final BinaryMessageDecoder<GreetingRecord> DECODER =
      new BinaryMessageDecoder<GreetingRecord>(MODEL$, SCHEMA$);

  /**
   * Return the BinaryMessageDecoder instance used by this class.
   */
  public static BinaryMessageDecoder<GreetingRecord> getDecoder() {
    return DECODER;
  }

  /**
   * Create a new BinaryMessageDecoder instance for this class that uses the specified {@link SchemaStore}.
   * @param resolver a {@link SchemaStore} used to find schemas by fingerprint
   */
  public static BinaryMessageDecoder<GreetingRecord> createDecoder(SchemaStore resolver) {
    return new BinaryMessageDecoder<GreetingRecord>(MODEL$, SCHEMA$, resolver);
  }

  /** Serializes this GreetingRecord to a ByteBuffer. */
  public java.nio.ByteBuffer toByteBuffer() throws java.io.IOException {
    return ENCODER.encode(this);
  }

  /** Deserializes a GreetingRecord from a ByteBuffer. */
  public static GreetingRecord fromByteBuffer(
      java.nio.ByteBuffer b) throws java.io.IOException {
    return DECODER.decode(b);
  }

  @Deprecated public java.lang.CharSequence message;

  /**
   * Default constructor.  Note that this does not initialize fields
   * to their default values from the schema.  If that is desired then
   * one should use <code>newBuilder()</code>.
   */
  public GreetingRecord() {}

  /**
   * All-args constructor.
   * @param message The new value for message
   */
  public GreetingRecord(java.lang.CharSequence message) {
    this.message = message;
  }

  public org.apache.avro.Schema getSchema() { return SCHEMA$; }
  // Used by DatumWriter.  Applications should not call.
  public java.lang.Object get(int field$) {
    switch (field$) {
    case 0: return message;
    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
    }
  }

  // Used by DatumReader.  Applications should not call.
  @SuppressWarnings(value="unchecked")
  public void put(int field$, java.lang.Object value$) {
    switch (field$) {
    case 0: message = (java.lang.CharSequence)value$; break;
    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
    }
  }

  /**
   * Gets the value of the 'message' field.
   * @return The value of the 'message' field.
   */
  public java.lang.CharSequence getMessage() {
    return message;
  }

  /**
   * Sets the value of the 'message' field.
   * @param value the value to set.
   */
  public void setMessage(java.lang.CharSequence value) {
    this.message = value;
  }

  /**
   * Creates a new GreetingRecord RecordBuilder.
   * @return A new GreetingRecord RecordBuilder
   */
  public static GreetingRecord.Builder newBuilder() {
    return new GreetingRecord.Builder();
  }

  /**
   * Creates a new GreetingRecord RecordBuilder by copying an existing Builder.
   * @param other The existing builder to copy.
   * @return A new GreetingRecord RecordBuilder
   */
  public static GreetingRecord.Builder newBuilder(GreetingRecord.Builder other) {
    return new GreetingRecord.Builder(other);
  }

  /**
   * Creates a new GreetingRecord RecordBuilder by copying an existing GreetingRecord instance.
   * @param other The existing instance to copy.
   * @return A new GreetingRecord RecordBuilder
   */
  public static GreetingRecord.Builder newBuilder(GreetingRecord other) {
    return new GreetingRecord.Builder(other);
  }

  /**
   * RecordBuilder for GreetingRecord instances.
   */
  public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase<GreetingRecord>
    implements org.apache.avro.data.RecordBuilder<GreetingRecord> {

    private java.lang.CharSequence message;

    /** Creates a new Builder */
    private Builder() {
      super(SCHEMA$);
    }

    /**
     * Creates a Builder by copying an existing Builder.
     * @param other The existing Builder to copy.
     */
    private Builder(GreetingRecord.Builder other) {
      super(other);
      if (isValidValue(fields()[0], other.message)) {
        this.message = data().deepCopy(fields()[0].schema(), other.message);
        fieldSetFlags()[0] = true;
      }
    }

    /**
     * Creates a Builder by copying an existing GreetingRecord instance
     * @param other The existing instance to copy.
     */
    private Builder(GreetingRecord other) {
            super(SCHEMA$);
      if (isValidValue(fields()[0], other.message)) {
        this.message = data().deepCopy(fields()[0].schema(), other.message);
        fieldSetFlags()[0] = true;
      }
    }

    /**
      * Gets the value of the 'message' field.
      * @return The value.
      */
    public java.lang.CharSequence getMessage() {
      return message;
    }

    /**
      * Sets the value of the 'message' field.
      * @param value The value of 'message'.
      * @return This builder.
      */
    public GreetingRecord.Builder setMessage(java.lang.CharSequence value) {
      validate(fields()[0], value);
      this.message = value;
      fieldSetFlags()[0] = true;
      return this;
    }

    /**
      * Checks whether the 'message' field has been set.
      * @return True if the 'message' field has been set, false otherwise.
      */
    public boolean hasMessage() {
      return fieldSetFlags()[0];
    }


    /**
      * Clears the value of the 'message' field.
      * @return This builder.
      */
    public GreetingRecord.Builder clearMessage() {
      message = null;
      fieldSetFlags()[0] = false;
      return this;
    }

    @Override
    @SuppressWarnings("unchecked")
    public GreetingRecord build() {
      try {
        GreetingRecord record = new GreetingRecord();
        record.message = fieldSetFlags()[0] ? this.message : (java.lang.CharSequence) defaultValue(fields()[0]);
        return record;
      } catch (java.lang.Exception e) {
        throw new org.apache.avro.AvroRuntimeException(e);
      }
    }
  }

  @SuppressWarnings("unchecked")
  private static final org.apache.avro.io.DatumWriter<GreetingRecord>
    WRITER$ = (org.apache.avro.io.DatumWriter<GreetingRecord>)MODEL$.createDatumWriter(SCHEMA$);

  @Override public void writeExternal(java.io.ObjectOutput out)
    throws java.io.IOException {
    WRITER$.write(this, SpecificData.getEncoder(out));
  }

  @SuppressWarnings("unchecked")
  private static final org.apache.avro.io.DatumReader<GreetingRecord>
    READER$ = (org.apache.avro.io.DatumReader<GreetingRecord>)MODEL$.createDatumReader(SCHEMA$);

  @Override public void readExternal(java.io.ObjectInput in)
    throws java.io.IOException {
    READER$.read(this, SpecificData.getDecoder(in));
  }

}

How solve problem with different classloader?

Answer 1

I find workaround here: @AuthenticationPrincipal with Spring Boot not working

public static void main(String[] args) {
System.setProperty("spring.devtools.restart.enabled", "false");
SpringApplication.run(MyApplication.class, args);

}

Turn off spring.devtools.restart solve issue:

Answer 2

I have a solution. As long as you use Spring, I guess you probably use Spring Devtools.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <scope>runtime</scope>
    <optional>true</optional>
</dependency>

Remove that dependency which causes the troubles:

org.springframework.kafka.listener.ListenerExecutionFailedException: Listener method 'public void org.company.MyKafkaConsumer.consume(org.apache.kafka.clients.consumer.ConsumerRecord<java.lang.String, org.mycompany.avro.MyAvroObject>,org.springframework.kafka.support.Acknowledgment)' threw exception; nested exception is java.lang.ClassCastException: class org.mycompany.avro.MyAvroObject cannot be cast to class org.mycompany.avro.MyAvroObject (org.mycompany.avro.MyAvroObject is in unnamed module of loader 'app'; org.mycompany.avro.MyAvroObject is in unnamed module of loader org.springframework.boot.devtools.restart.classloader.RestartClassLoader @3a9df291); nested exception is java.lang.ClassCastException: class org.mycompany.avro.MyAvroObject cannot be cast to class org.mycompany.avro.MyAvroObject (org.mycompany.avro.MyAvroObject is in unnamed module of loader 'app'; org.mycompany.avro.MyAvroObject is in unnamed module of loader org.springframework.boot.devtools.restart.classloader.RestartClassLoader @3a9df291)
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.decorateException(KafkaMessageListenerContainer.java:1899) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.invokeErrorHandler(KafkaMessageListenerContainer.java:1887) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.doInvokeRecordListener(KafkaMessageListenerContainer.java:1792) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.doInvokeWithRecords(KafkaMessageListenerContainer.java:1719) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.invokeRecordListener(KafkaMessageListenerContainer.java:1617) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.invokeListener(KafkaMessageListenerContainer.java:1348) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.pollAndInvoke(KafkaMessageListenerContainer.java:1064) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.run(KafkaMessageListenerContainer.java:972) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) ~[na:na]
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
    at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
Caused by: java.lang.ClassCastException: class org.mycompany.avro.MyAvroObject cannot be cast to class org.mycompany.avro.MyAvroObject (org.mycompany.avro.MyAvroObject is in unnamed module of loader 'app'; org.mycompany.avro.MyAvroObject is in unnamed module of loader org.springframework.boot.devtools.restart.classloader.RestartClassLoader @3a9df291)
    at org.company.MyKafkaConsumer.consume(NiaKafkaConsumer.java:33) ~[classes/:na]
    at jdk.internal.reflect.GeneratedMethodAccessor81.invoke(Unknown Source) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:171) ~[spring-messaging-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:120) ~[spring-messaging-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.kafka.listener.adapter.HandlerAdapter.invoke(HandlerAdapter.java:48) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:334) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.adapter.RecordMessagingMessageListenerAdapter.onMessage(RecordMessagingMessageListenerAdapter.java:86) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.adapter.RecordMessagingMessageListenerAdapter.onMessage(RecordMessagingMessageListenerAdapter.java:51) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.doInvokeOnMessage(KafkaMessageListenerContainer.java:1854) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.invokeOnMessage(KafkaMessageListenerContainer.java:1836) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.doInvokeRecordListener(KafkaMessageListenerContainer.java:1779) ~[spring-kafka-2.5.2.RELEASE.jar:2.5.2.RELEASE]
    ... 8 common frames omitted