How to catch a specific exception in JDBC?

Question

How to catch specific exceptions in JDBC? Examples: primary key exception or foreign key exception.

Answer 1

The best and DB-independent way to handle SQLException more specifically is to determine the SQL state code which can be obtained by SQLException#getSQLState(). The SQLState is a 5-char code, of which the first two are common among all DB's and the last three might differ depending on the DB and/or the specific condition. Here's an extract from the spec:

• 02: no data
• 07: dynamic SQL error
• 08: connection exception
• 0A: feature not supported
• 21: cardinality violation
• 22: data exception
• 23: integrity constraint violation
• 24: invalid cursor state
• 25: invalid transaction state
• 26: invalid SQL statement name
• 28: invalid authorization specification
• 2B: dependent privilege descriptors still exist
• 2C: invalid character set name
• 2D: invalid transaction termination
• 2E: invalid connection name
• 33: invalid SQL descriptor name
• 34: invalid cursor name
• 35: invalid condition number
• 3C: ambiguous cursor name
• 3D: invalid catalog name
• 3F: invalid schema name

So to determine whether the SQL Exception is caused by a constraint violation, you can just do the following in a (fictive) SQLUtil class:

public static boolean isConstraintViolation(SQLException e) {
    return e.getSQLState().startsWith("23");
}