Spring Batch: org.springframework.batch.item.ReaderNotOpenException: Reader must be open before it can be read

Question

I read SO related questions but the solutions don\'t work for me.

I get the org.springframework.batch.item.ReaderNotOpenException: Reader must be open before i

Answer 1

The method I defined is like below:

    @Bean
    @StepScope
    public ItemReader BPReader(){
       
        JdbcCursorItemReader itemReader = new JdbcCursorItemReader();
        ...
        return itemReader;
    }

The type I defined in the method is ItemReader which is an interface, the return type is JdbcCursorItemReader which is a sub-class of it. By changing the return type defination to JdbcCursorItemReader solved my problem