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| java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0 |
{getToc} $title={Table of Contents} $count={true}
Error
I have this kind of function to get nation from DB for a single value.
public String getUsrNationKh(long userId) throws Exception {
return owpJdbcTemplate.queryForObject(SQL_GET_NATIOKH, String.class, userId);
}
And I got this kind of error whenever it's empty result.
java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0.
Understanding the Error
The error java.lang.IndexOutOfBoundsException: Index 0 out of bounds for
length 0" occurs when trying to access an element at index 0 in an empty array
or list. In this case, it happens when the queryForObject method expects a
result but gets an empty result set.
The exception is thrown by Spring's queryForObject method when the result is
expected to be a single result, but none is found.
Solution
To handle the case where the query returns an empty result and avoid the
IndexOutOfBoundsException, we can modify the code to catch the exception and
return null in such cases. Here's an updated version of the function:
public String getUsrNationKh(long userId) {
try {
return owpJdbcTemplate.queryForObject(SQL_GET_NATIOKH, String.class, userId);
} catch (EmptyResultDataAccessException e) {
// Handle empty result by returning null
return null;
} catch (Exception e) {
// Handle other exceptions as needed, or rethrow if necessary
throw new RuntimeException("Error retrieving user nation", e);
}
}
In this modification, I've added a try-catch block to catch the
EmptyResultDataAccessException specifically. This exception is thrown by
Spring's queryForObject method when the result is expected to be a single
result, but none is found. By catching this exception, we can return null in
case of an empty result. Other exceptions are caught separately, and we can
customize the error handling based on our requirements.
The solution provided involves catching the EmptyResultDataAccessException,
which is thrown by Spring's queryForObject when no result is found. By
catching this exception, we can handle the empty result case and return null
instead of encountering the index out of bounds issue.
Conclusion
The modification to the code is a good approach to gracefully handle the
situation where the query returns no results, preventing the
IndexOutOfBoundsException and allowing the function to return null in such
cases.
