When querying database, exceptions might appear. JDBC provides getMessage() and getErrorCode() methods to handle those exceptions.:
try
{
Statement s = conn.createStatement ();
s.executeQuery ("XYZ"); // issue invalid query
s.close ();
}
catch (SQLException e)
{
System.err.println ("Error message: " + e.getMessage ());
System.err.println ("Error number: " + e.getErrorCode ());
}