Jackson mismatched input error

May 2, 2021

Suppose you are trying to do something like:

@Bean
public MyConfiguration myConfiguration() throws IOException {
    ObjectMapper yamlMapper = new ObjectMapper(new YAMLFactory());
    return yamlMapper.readValue(new File("configuration.yml"), MyConfiguration.class);
}

But the output is something like:

com.fasterxml.jackson.databind.exc.MismatchedInputException

There are at least two reasons:

Configuration file does not exist;
Setters for MyConfiguration.class are named incorrectly or cannot be accessed.