InvalidDefinitionException is an exception class in the Jackson library that is thrown when a problem with the definition of a type is encountered during serialization or deserialization.

It is a sub-class of MismatchedInputException which is a more general exception that is thrown when the input does not match the expected structure.

Here is an example of how InvalidDefinitionException can be thrown:

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) {
        ObjectMapper mapper = new ObjectMapper();
        String jsonString = "{\"name\":\"John\",\"age\":\"20\"}";
        try {
            Person person = mapper.readValue(jsonString, Person.class);
        } catch (JsonMappingException e) {
            if (e instanceof InvalidDefinitionException) {
                InvalidDefinitionException ex = (InvalidDefinitionException) e;
                System.err.println("Invalid Definition exception: " + ex.getMessage());
            }
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
    }
}
class Person {
    private String name;
    private int age;
    //getters, setters and constructors
}

In this example, the json string jsonString is being deserialized to an object of type Person, but the age field in the json string is a string while the age field in the Person class is of type int.

This causes InvalidDefinitionException to be thrown, which is caught and printed.

It's important to note that this is just an example and the real-world usage of this exception would depend on the specific use-case, for example, you can return a custom error message or log the exception.