该错误一般是因为使用了较老的 Pulsar 版本所导致的。解决方法是将 Pulsar 升级到较新的版本。同时，建议使用最近更新的 Pulsar API 来操作 schema。以下是一个示例，展示了在 Pulsar 2.8.1 中使用 Schema 的建议方法：

import org.apache.pulsar.client.api.Schema;
import org.apache.pulsar.client.api.schema.*;

public class PulsarSchemaDemo {

    public static void main(String[] args) throws PulsarClientException {

        PulsarClient client = PulsarClient.builder()
                .serviceUrl("pulsar://localhost:6650")
                .build();

        CustomerSchema customerSchema = new CustomerSchema();

        Producer producer = client.newProducer(customerSchema)
                .topic("persistent://my-tenant/my-namespace/my-topic")
                .create();

        Customer myCustomer = new Customer();
        myCustomer.setName("John");
        myCustomer.setAge(35);

        producer.send(myCustomer);

        consumer.close();
        client.close();
    }

    private static class Customer {
        String name;
        int age;

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getAge() {
            return age;
        }

        public void setAge(int age) {
            this.age = age;
        }
    }

    private static class CustomerSchema implements Schema {

        @Override
        public byte[] encode(Customer message) throws SchemaSerializationException {
            // Encode Customer object to byte array
        }

        @Override
        public Customer decode(byte[] bytes) throws SchemaSerializationException {
            // Decode byte array to Customer object
        }

        @Override
        public SchemaInfo getSchemaInfo() {
            // Create SchemaInfo object with schema details
        }
    }
}