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JSONSchema should works with generic (parameterized type) POJO/DTO.

See original GitHub issue

Expected behavior

JSONSchema should works with generic (parameterized type) POJO/DTO. No exception at runtime, or at least update documentation/errorMessage how to work-around/bypass the issue.

Actual behavior

Exception when running producer/consumer with JSONSchema.of(clazz) (or Schema.JSON(clazz) ) wiith generic/parameterized class:

Exception in thread "main" java.lang.NoSuchFieldError: KEY_VALUE
	at org.apache.pulsar.client.impl.schema.KeyValueSchema.<init>(KeyValueSchema.java:50)
	at org.apache.pulsar.client.api.Schema.<clinit>(Schema.java:128)

Steps to reproduce

Create Producer or Consumer with client API, using JSONSchema.of(clazz) (or Schema.JSON(clazz) ) wiith generic/parameterized class. Compiled OK, but when running the client producer/consumer it throws exception.

Example (https://github.com/ducquoc/pulsar/commit/a0649dc8): https://github.com/ducquoc/pulsar/blob/fix-client-schema_json-schema-generic-parameterized-type/pulsar-functions/java-examples/src/main/java/org/apache/pulsar/functions/api/examples/pojo/BrokerMessage.java

** Work-around: use

private Object payload;

and respective getter/setter instead of

private T payload;

System configuration

Pulsar version: 2.2.0 (but seems to be also affected on latest master branch)

Issue Analytics

State:
Created 5 years ago
Comments:16 (6 by maintainers)

Top GitHub Comments

2reactions

rohts-patilcommented, Nov 29, 2019

@vamsi360 ,

I cloned your fork and built it to version 1.8.3-ppe-9.10. I still get the errror.

Caused by: org.apache.avro.AvroTypeException: Unknown type: T
	at org.apache.avro.specific.SpecificData.createSchema(SpecificData.java:312)
	at org.apache.avro.reflect.ReflectData.createSchema(ReflectData.java:720)
	at org.apache.avro.reflect.ReflectData.createFieldSchema(ReflectData.java:870)
	at org.apache.avro.reflect.ReflectData.createSchema(ReflectData.java:686)
	at org.apache.avro.specific.SpecificData$2.load(SpecificData.java:238)
	at org.apache.avro.specific.SpecificData$2.load(SpecificData.java:235)
	at avro.shaded.com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3568)
	at avro.shaded.com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2350)
	at avro.shaded.com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2313)
	at avro.shaded.com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2228)
	... 6 more

1reaction

frankjkellycommented, Sep 8, 2020

We too have been hit by this issue trying to send generics