# We're seeing Class io.confluent.kafka.serializers.context.NullContextNameStrategy could not be found error intermittently

**URL:** <https://forum.confluent.io/t/were-seeing-class-io-confluent-kafka-serializers-context-nullcontextnamestrategy-could-not-be-found-error-intermittently/7884>\
**Category:** Java Clients\
**Created:** [17 May 2023 09:25 UTC](https://forum.confluent.io/t/were-seeing-class-io-confluent-kafka-serializers-context-nullcontextnamestrategy-could-not-be-found-error-intermittently/7884 "2023-05-17T09:25:57Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![SanjayPatil](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@SanjayPatil](https://forum.confluent.io/u/SanjayPatil)\
**Post date:** [17 May 2023 09:25 UTC](https://forum.confluent.io/t/were-seeing-class-io-confluent-kafka-serializers-context-nullcontextnamestrategy-could-not-be-found-error-intermittently/7884/1 "2023-05-17T09:25:57Z")

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We’re seeing below error when our SpringBoot producer is idle for long time. Normally the producer is able to send messages to confluent kafka successfully. However few times application failed with following error. This error goes away when we restart the application.

Caused by: java.lang.NoClassDefFoundError: Could not initialize class io.confluent.kafka.serializers.KafkaAvroSerializerConfig  
at io.confluent.kafka.serializers.KafkaAvroSerializer.configure(KafkaAvroSerializer.java:51) ~[kafka-avro-serializer-7.4.0.jar!/:na]  
at org.apache.kafka.clients.producer.KafkaProducer.(KafkaProducer.java:390) ~[kafka-clients-3.4.0.jar!/:na]  
… 36 common frames omitted  
Caused by: java.lang.ExceptionInInitializerError: Exception org.apache.kafka.common.config.ConfigException: Invalid value io.confluent.kafka.serializers.context.NullContextNameStrategy for configuration context.name.strategy: Class io.confluent.kafka.serializers.context.NullContextNameStrategy could not be found. [in thread “ForkJoinPool.commonPool-worker-1”]  
at org.apache.kafka.common.config.ConfigDef.parseType(ConfigDef.java:744) ~[kafka-clients-3.4.0.jar!/:na]  
at org.apache.kafka.common.config.ConfigDef$ConfigKey.(ConfigDef.java:1172) ~[kafka-clients-3.4.0.jar!/:na]  
at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:152) ~[kafka-clients-3.4.0.jar!/:na]  
at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:172) ~[kafka-clients-3.4.0.jar!/:na]  
at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:211) ~[kafka-clients-3.4.0.jar!/:na]  
at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:373) ~[kafka-clients-3.4.0.jar!/:na]  
at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:386) ~[kafka-clients-3.4.0.jar!/:na]  
at io.confluent.kafka.serializers.AbstractKafkaSchemaSerDeConfig.baseConfigDef(AbstractKafkaSchemaSerDeConfig.java:310) ~[kafka-schema-serializer-7.4.0.jar!/:na]  
at io.confluent.kafka.serializers.KafkaAvroSerializerConfig.(KafkaAvroSerializerConfig.java:43) ~[kafka-avro-serializer-7.4.0.jar!/:na]

We’re using below dependencies in our Sprint Boot application

```
    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-clients</artifactId>
        <version>3.4.0</version>
    </dependency>

    <dependency>
        <groupId>io.confluent</groupId>
        <artifactId>kafka-avro-serializer</artifactId>
        <version>7.4.0</version>
    </dependency>
    <dependency>
        <groupId>io.confluent</groupId>
        <artifactId>kafka-schema-serializer</artifactId>
        <version>7.4.0</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.kafka</groupId>
        <artifactId>spring-kafka</artifactId>
        <version>3.0.6</version>
        <exclusions>
            <exclusion>
                <groupId>org.apache.kafka</groupId>
                <artifactId>kafka-clients</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

```

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<div class="post-metadata">

**Author:** ![OneCricketeer](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.confluent.io/onecricketeer/32/1551_2.png) [@OneCricketeer](https://forum.confluent.io/u/OneCricketeer)\
**Post date:** [23 June 2023 03:28 UTC](https://forum.confluent.io/t/were-seeing-class-io-confluent-kafka-serializers-context-nullcontextnamestrategy-could-not-be-found-error-intermittently/7884/2 "2023-06-23T03:28:14Z")

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Have you tried explicitly setting a serializer subject name strategy in your Spring-kafka producer config?