What is the reason for getting an IllegalArgumentException exception during a database query?

IllegalArgumentException exception refers to when the parameters of a method are invalid or unreasonable, which could be caused by the following reasons:

1. Empty parameters: passing empty parameter values in a query statement, such as passing an empty string or null value.
2. Parameter type error: The type of parameter passed does not match the type of parameter required by the method, for example, passing a string type parameter when the method requires an integer type parameter.
3. The parameter value is out of range: the parameter value passed has exceeded the range specified by the method, such as passing a negative number as an array index.
4. The parameter format is incorrect: the format of the input parameter does not meet the requirements of the method, such as an incorrect date string format.
5. The parameter order is incorrect: The order of the parameters passed is not correct, such as when the order of the parameters passed does not match the order defined in the method.
6. Database connection error: Issues with the database connection, such as timeout or closure of the connection.

When encountering an IllegalArgumentException, it is important to check if the parameters passed in the code meet the method requirements to ensure their validity. It is also necessary to verify the status of the database connection and ensure that the related database operations are correct.