Buenas,

Mi problema es un poco extraño. La primera vez que utilice la librería "mysql-connector-java-5.1.14-bin" me encontré con el problema, la segunda vez que hice un ejemplo no salio el problema, pero ahora cuando voy a hacer un ejemplo más serio vuelvo a tener un problema con ella. Os cuento, yo añado la librería al proyecto pero no llego a utilizarla y me sale lo siguiente(y no se ejecuta la aplicación...):

____________________________________________________________________

<ConnectionProperties>  <PropertyCategory name="Connection/Authentication">   <Property name="user" required="No" default="" sortOrder="-2147483647" since="all versions">     The user to connect as   </Property>   <Property name="password" required="No" default="" sortOrder="-2147483646" since="all versions">     The password to use when connecting   </Property>   <Property name="socketFactory" required="No" default="com.mysql.jdbc.StandardSocketFactory" sortOrder="4" since="3.0.3">     The name of the class that the driver should use for creating socket connections to the server. This class must implement the interface 'com.mysql.jdbc.SocketFactory' and have public no-args constructor.   </Property>   <Property name="connectTimeout" required="No" default="0" sortOrder="9" since="3.0.1">     Timeout for socket connect (in milliseconds), with 0 being no timeout. Only works on JDK-1.4 or newer. Defaults to '0'.   </Property>   <Property name="socketTimeout" required="No" default="0" sortOrder="10" since="3.0.1">     Timeout on network socket operations (0, the default means no timeout).   </Property>   <Property name="connectionLifecycleInterceptors" required="No" default="" sortOrder="2147483647" since="5.1.4">     A comma-delimited list of classes that implement "com.mysql.jdbc.ConnectionLifecycleInterceptor" that should notified of connection lifecycle events (creation, destruction, commit, rollback, setCatalog and setAutoCommit) and potentially alter the execution of these commands. ConnectionLifecycleInterceptors are "stackable", more than one interceptor may be specified via the configuration property as a comma-delimited list, with the interceptors executed in order from left to right.   </Property>   <Property name="useConfigs" required="No" default="" sortOrder="2147483647" since="3.1.5">     Load the comma-delimited list of configuration properties before parsing the URL or applying user-specified properties. These configurations are explained in the 'Configurations' of the documentation.   </Property>   <Property name="interactiveClient" required="No" default="false" sortOrder="alpha" since="3.1.0">     Set the CLIENT_INTERACTIVE flag, which tells MySQL to timeout connections based on INTERACTIVE_TIMEOUT instead of WAIT_TIMEOUT   </Property>   <Property name="localSocketAddress" required="No" default="" sortOrder="alpha" since="5.0.5">     Hostname or IP address given to explicitly configure the interface that the driver will bind the client side of the TCP/IP connection to when connecting.   </Property>   <Property name="propertiesTransform" required="No" default="" sortOrder="alpha" since="3.1.4">     An implementation of com.mysql.jdbc.ConnectionPropertiesTransform that the driver will use to modify URL properties passed to the driver before attempting a connection   </Property>   <Property name="useCompression" required="No" default="false" sortOrder="alpha" since="3.0.17">     Use zlib compression when communicating with the server (true/false)? Defaults to 'false'.   </Property>  </PropertyCategory>  <PropertyCategory name="Networking">   <Property name="maxAllowedPacket" required="No" default="-1" sortOrder="alpha" since="5.1.8">     Maximum allowed packet size to send to server. If not set, the value of system variable 'max_allowed_packet' will be used to initialize this upon connecting. This value will not take effect if set larger than the value of 'max_allowed_packet'.   </Property>   <Property name="tcpKeepAlive" required="No" default="true" sortOrder="alpha" since="5.0.7">     If connecting using TCP/IP, should the driver set SO_KEEPALIVE?   </Property>   <Property name="tcpNoDelay" required="No" default="true" sortOrder="alpha" since="5.0.7">     If connecting using TCP/IP, should the driver set SO_TCP_NODELAY (disabling the Nagle Algorithm)?   </Property>   <Property name="tcpRcvBuf" required="No" default="0" sortOrder="alpha" since="5.0.7">     If connecting using TCP/IP, should the driver set SO_RCV_BUF to the given value? The default value of '0', means use the platform default value for this property)   </Property>   <Property name="tcpSndBuf" required="No" default="0" sortOrder="alpha" since="5.0.7">     If connecting using TCP/IP, shuold the driver set SO_SND_BUF to the given value? The default value of '0', means use the platform default value for this property)   </Property>   <Property name="tcpTrafficClass" required="No" default="0" sortOrder="alpha" since="5.0.7">     If connecting using TCP/IP, should the driver set traffic class or type-of-service fields ?See the documentation for java.net.Socket.setTrafficClass() for more information.   </Property>  </PropertyCategory>  <PropertyCategory name="High Availability and Clustering">   <Property name="autoReconnect" required="No" default="false" sortOrder="0" since="1.1">     Should the driver try to re-establish stale and/or dead connections? If enabled the driver will throw an exception for a queries issued on a stale or dead connection, which belong to the current transaction, but will attempt reconnect before the next query issued on the connection in a new transaction. The use of this feature is not recommended, because it has side effects related to session state and data consistency when applications don't handle SQLExceptions properly, and is only designed to be used when you are unable to configure your application to handle SQLExceptions resulting from dead and stale connections properly. Alternatively, investigate setting the MySQL server variable "wait_timeout" to some high value rather than the default of 8 hours.   </Property>   <Property name="autoReconnectForPools" required="No" default="false" sortOrder="1" since="3.1.3">     Use a reconnection strategy appropriate for connection pools (defaults to 'false')   </Property>   <Property name="failOverReadOnly" required="No" default="true" sortOrder="2" since="3.0.12">     When failing over in autoReconnect mode, should the connection be set to 'read-only'?   </Property>   <Property name="maxReconnects" required="No" default="3" sortOrder="4" since="1.1">     Maximum number of reconnects to attempt if autoReconnect is true, default is '3'.   </Property>   <Property name="reconnectAtTxEnd" required="No" default="false" sortOrder="4" since="3.0.10">     If autoReconnect is set to true, should the driver attempt reconnections at the end of every transaction?   </Property>   <Property name="retriesAllDown" required="No" default="120" sortOrder="4" since="5.1.6">     When using loadbalancing, the number of times the driver should cycle through available hosts, attempting to connect.  Between cycles, the driver will pause for 250ms if no servers are available.   </Property>   <Property name="initialTimeout" required="No" default="2" sortOrder="5" since="1.1">     If autoReconnect is enabled, the initial time to wait between re-connect attempts (in seconds, defaults to '2').   </Property>   <Property name="roundRobinLoadBalance" required="No" default="false" sortOrder="5" since="3.1.2">     When autoReconnect is enabled, and failoverReadonly is false, should we pick hosts to connect to on a round-robin basis?   </Property>   <Property name="queriesBeforeRetryMaster" required="No" default="50" sortOrder="7" since="3.0.2">     Number of queries to issue before falling back to master when failed over (when using multi-host failover). Whichever condition is met first, 'queriesBeforeRetryMaster' or 'secondsBeforeRetryMaster' will cause an attempt to be made to reconnect to the master. Defaults to 50.   </Property>   <Property name="secondsBeforeRetryMaster" required="No" default="30" sortOrder="8" since="3.0.2">     How long should the driver wait, when failed over, before attempting   </Property>   <Property name="selfDestructOnPingMaxOperations" required="No" default="0" sortOrder="2147483647" since="5.1.6">     =If set to a non-zero value, the driver will report close the connection and report failure when Connection.ping() or Connection.isValid(int) is called if the connnection's count of commands sent to the server exceeds this value.   </Property>   <Property name="selfDestructOnPingSecondsLifetime" required="No" default="0" sortOrder="2147483647" since="5.1.6">     If set to a non-zero value, the driver will report close the connection and report failure when Connection.ping() or Connection.isValid(int) is called if the connnection's lifetime exceeds this value.   </Property>   <Property name="resourceId" required="No" default="" sortOrder="alpha" since="5.0.1">     A globally unique name that identifies the resource that this datasource or connection is connected to, used for XAResource.isSameRM() when the driver can't determine this value based on hostnames used in the URL   </Property>  </PropertyCategory>  <PropertyCategory name="Security">   <Property name="allowMultiQueries" required="No" default="false" sortOrder="1" since="3.1.1">     Allow the use of ';' to delimit multiple queries during one statement (true/false), defaults to 'false'   </Property>   <Property name="useSSL" required="No" default="false" sortOrder="2" since="3.0.2">     Use SSL when communicating with the server (true/false), defaults to 'false'   </Property>   <Property name="requireSSL" required="No" default="false" sortOrder="3" since="3.1.0">     Require SSL connection if useSSL=true? (defaults to 'false').   </Property>   <Property name="verifyServerCertificate" required="No" default="true" sortOrder="4" since="5.1.6">     If "useSSL" is set to "true", should the driver verify the server's certificate? When using this feature, the keystore parameters should be specified by the "clientCertificateKeyStore*" properties, rather than system properties.   </Property>   <Property name="clientCertificateKeyStoreUrl" required="No" default="" sortOrder="5" since="5.1.0">     URL to the client certificate KeyStore (if not specified, use defaults)   </Property>   <Property name="clientCertificateKeyStoreType" required="No" default="JKS" sortOrder="6" since="5.1.0">     KeyStore type for client certificates (NULL or empty means use the default, which is "JKS". Standard keystore types supported by the JVM are "JKS" and "PKCS12", your environment may have more available depending on what security products are installed and available to the JVM.   </Property>   <Property name="clientCertificateKeyStorePassword" required="No" default="" sortOrder="7" since="5.1.0">     Password for the client certificates KeyStore   </Property>   <Property name="trustCertificateKeyStoreUrl" required="No" default="" sortOrder="8" since="5.1.0">     URL to the trusted root certificate KeyStore (if not specified, use defaults)   </Property>   <Property name="trustCertificateKeyStoreType" required="No" default="JKS" sortOrder="9" since="5.1.0">     KeyStore type for trusted root certificates (NULL or empty means use the default, which is "JKS". Standard keystore types supported by the JVM are "JKS" and "PKCS12", your environment may have more available depending on what security products are installed and available to the JVM.   </Property>   <Property name="trustCertificateKeyStorePassword" required="No" default="" sortOrder="10" since="5.1.0">     Password for the trusted root certificates KeyStore   </Property>   <Property name="allowLoadLocalInfile" required="No" default="true" sortOrder="2147483647" since="3.0.3">     Should the driver allow use of 'LOAD DATA LOCAL INFILE...' (defaults to 'true').   </Property>   <Property name="allowUrlInLocalInfile" required="No" default="false" sortOrder="2147483647" since="3.1.4">     Should the driver allow URLs in 'LOAD DATA LOCAL INFILE' statements?   </Property>   <Property name="paranoid" required="No" default="false" sortOrder="alpha" since="3.0.1">     Take measures to prevent exposure sensitive information in error messages and clear data structures holding sensitive data when possible? (defaults to 'false')   </Property>   <Property name="passwordCharacterEncoding" required="No" default="" sortOrder="alpha" since="5.1.7">     What character encoding is used for passwords? Leaving this set to the default value (null), uses the platform character set, which works for ISO8859_1 (i.e. "latin1") passwords. For passwords in other character encodings, the encoding will have to be specified with this property, as it's not possible for the driver to auto-detect this.   </Property>  </PropertyCategory>  <PropertyCategory name="Performance Extensions">   <Property name="callableStmtCacheSize" required="No" default="100" sortOrder="5" since="3.1.2">     If 'cacheCallableStmts' is enabled, how many callable statements should be cached?   </Property>   <Property name="metadataCacheSize" required="No" default="50" sortOrder="5" since="3.1.1">     The number of queries to cache ResultSetMetadata for if cacheResultSetMetaData is set to 'true' (default 50)   </Property>   <Property name="useLocalSessionState" required="No" default="false" sortOrder="5" since="3.1.7">     Should the driver refer to the internal values of autocommit and transaction isolation that are set by Connection.setAutoCommit() and Connection.setTransactionIsolation() and transaction state as maintained by the protocol, rather than querying the database or blindly sending commands to the database for commit() or rollback() method calls?   </Property>   <Property name="useLocalTransactionState" required="No" default="false" sortOrder="6" since="5.1.7">     Should the driver use the in-transaction state provided by the MySQL protocol to determine if a commit() or rollback() should actually be sent to the database?   </Property>   <Property name="prepStmtCacheSize" required="No" default="25" sortOrder="10" since="3.0.10">     If prepared statement caching is enabled, how many prepared statements should be cached?   </Property>   <Property name="prepStmtCacheSqlLimit" required="No" default="256" sortOrder="11" since="3.0.10">     If prepared statement caching is enabled, what's the largest SQL the driver will cache the parsing for?   </Property>   <Property name="alwaysSendSetIsolation" required="No" default="true" sortOrder="2147483647" since="3.1.7">     Should the driver always communicate with the database when Connection.setTransactionIsolation() is called? If set to false, the driver will only communicate with the database when the requested transaction isolation is different than the whichever is newer, the last value that was set via Connection.setTransactionIsolation(), or the value that was read from the server when the connection was established.   </Property>   <Property name="maintainTimeStats" required="No" default="true" sortOrder="2147483647" since="3.1.9">     Should the driver maintain various internal timers to enable idle time calculations as well as more verbose error messages when the connection to the server fails? Setting this property to false removes at least two calls to System.getCurrentTimeMillis() per query.   </Property>   <Property name="useCursorFetch" required="No" default="false" sortOrder="2147483647" since="5.0.0">     If connected to MySQL > 5.0.2, and setFetchSize() > 0 on a statement, should that statement use cursor-based fetching to retrieve rows?   </Property>   <Property name="blobSendChunkSize" required="No" default="1048576" sortOrder="alpha" since="3.1.9">     Chunk to use when sending BLOB/CLOBs via ServerPreparedStatements   </Property>   <Property name="cacheCallableStmts" required="No" default="false" sortOrder="alpha" since="3.1.2">     Should the driver cache the parsing stage of CallableStatements   </Property>   <Property name="cachePrepStmts" required="No" default="false" sortOrder="alpha" since="3.0.10">     Should the driver cache the parsing stage of PreparedStatements of client-side prepared statements, the "check" for suitability of server-side prepared and server-side prepared statements themselves?   </Property>   <Property name="cacheResultSetMetadata" required="No" default="false" sortOrder="alpha" since="3.1.1">     Should the driver cache ResultSetMetaData for Statements and PreparedStatements? (Req. JDK-1.4+, true/false, default 'false')   </Property>   <Property name="cacheServerConfiguration" required="No" default="false" sortOrder="alpha" since="3.1.5">     Should the driver cache the results of 'SHOW VARIABLES' and 'SHOW COLLATION' on a per-URL basis?   </Property>   <Property name="defaultFetchSize" required="No" default="0" sortOrder="alpha" since="3.1.9">     The driver will call setFetchSize(n) with this value on all newly-created Statements   </Property>   <Property name="dontTrackOpenResources" required="No" default="false" sortOrder="alpha" since="3.1.7">     The JDBC specification requires the driver to automatically track and close resources, however if your application doesn't do a good job of explicitly calling close() on statements or result sets, this can cause memory leakage. Setting this property to true relaxes this constraint, and can be more memory efficient for some applications.   </Property>   <Property name="dynamicCalendars" required="No" default="false" sortOrder="alpha" since="3.1.5">     Should the driver retrieve the default calendar when required, or cache it per connection/session?   </Property>   <Property name="elideSetAutoCommits" required="No" default="false" sortOrder="alpha" since="3.1.3">     If using MySQL-4.1 or newer, should the driver only issue 'set autocommit=n' queries when the server's state doesn't match the requested state by Connection.setAutoCommit(boolean)?   </Property>   <Property name="enableQueryTimeouts" required="No" default="true" sortOrder="alpha" since="5.0.6">     When enabled, query timeouts set via Statement.setQueryTimeout() use a shared java.util.Timer instance for scheduling. Even if the timeout doesn't expire before the query is processed, there will be memory used by the TimerTask for the given timeout which won't be reclaimed until the time the timeout would have expired if it hadn't been cancelled by the driver. High-load environments might want to consider disabling this functionality.   </Property>   <Property name="holdResultsOpenOverStatementClose" required="No" default="false" sortOrder="alpha" since="3.1.7">     Should the driver close result sets on Statement.close() as required by the JDBC specification?   </Property>   <Property name="largeRowSizeThreshold" required="No" default="2048" sortOrder="alpha" since="5.1.1">     What size result set row should the JDBC driver consider "large", and thus use a more memory-efficient way of representing the row internally?   </Property>   <Property name="loadBalanceStrategy" required="No" default="random" sortOrder="alpha" since="5.0.6">     If using a load-balanced connection to connect to SQL nodes in a MySQL Cluster/NDB configuration (by using the URL prefix "jdbc:mysql:loadbalance://"), which load balancing algorithm should the driver use: (1) "random" - the driver will pick a random host for each request. This tends to work better than round-robin, as the randomness will somewhat account for spreading loads where requests vary in response time, while round-robin can sometimes lead to overloaded nodes if there are variations in response times across the workload. (2) "bestResponseTime" - the driver will route the request to the host that had the best response time for the previous transaction.   </Property>   <Property name="locatorFetchBufferSize" required="No" default="1048576" sortOrder="alpha" since="3.2.1">     If 'emulateLocators' is configured to 'true', what size buffer should be used when fetching BLOB data for getBinaryInputStream?   </Property>   <Property name="rewriteBatchedStatements" required="No" default="false" sortOrder="alpha" since="3.1.13">     Should the driver use multiqueries (irregardless of the setting of "allowMultiQueries") as well as rewriting of prepared statements for INSERT into multi-value inserts when executeBatch() is called? Notice that this has the potential for SQL injection if using plain java.sql.Statements and your code doesn't sanitize input correctly. Notice that for prepared statements, server-side prepared statements can not currently take advantage of this rewrite option, and that if you don't specify stream lengths when using PreparedStatement.set*Stream(), the driver won't be able to determine the optimum number of parameters per batch and you might receive an error from the driver that the resultant packet is too large. Statement.getGeneratedKeys() for these rewritten statements only works when the entire batch includes INSERT statements.   </Property>   <Property name="useDirectRowUnpack" required="No" default="true" sortOrder="alpha" since="5.1.1">     Use newer result set row unpacking code that skips a copy from network buffers  to a MySQL packet instance and instead reads directly into the result set row data buffers.   </Property>   <Property name="useDynamicCharsetInfo" required="No" default="true" sortOrder="alpha" since="5.0.6">     Should the driver use a per-connection cache of character set information queried from the server when necessary, or use a built-in static mapping that is more efficient, but isn't aware of custom character sets or character sets implemented after the release of the JDBC driver?   </Property>   <Property name="useFastDateParsing" required="No" default="true" sortOrder="alpha" since="5.0.5">     Use internal String->Date/Time/Timestamp conversion routines to avoid excessive object creation?   </Property>   <Property name="useFastIntParsing" required="No" default="true" sortOrder="alpha" since="3.1.4">     Use internal String->Integer conversion routines to avoid excessive object creation?   </Property>   <Property name="useJvmCharsetConverters" required="No" default="false" sortOrder="alpha" since="5.0.1">     Always use the character encoding routines built into the JVM, rather than using lookup tables for single-byte character sets?   </Property>   <Property name="useReadAheadInput" required="No" default="true" sortOrder="alpha" since="3.1.5">     Use newer, optimized non-blocking, buffered input stream when reading from the server?   </Property>  </PropertyCategory>  <PropertyCategory name="Debugging/Profiling">   <Property name="logger" required="No" default="com.mysql.jdbc.log.StandardLogger" sortOrder="0" since="3.1.1">     The name of a class that implements "com.mysql.jdbc.log.Log"  that will be used to log messages to. (default is "com.mysql.jdbc.log.StandardLogger", which logs to STDERR)   </Property>   <Property name="gatherPerfMetrics" required="No" default="false" sortOrder="1" since="3.1.2">     Should the driver gather performance metrics, and report them via the configured logger every 'reportMetricsIntervalMillis' milliseconds?   </Property>   <Property name="profileSQL" required="No" default="false" sortOrder="1" since="3.1.0">     Trace queries and their execution/fetch times to the configured logger (true/false) defaults to 'false'   </Property>   <Property name="profileSql" required="No" default="" sortOrder="3" since="2.0.14">     Deprecated, use 'profileSQL' instead. Trace queries and their execution/fetch times on STDERR (true/false) defaults to 'false'   </Property>   <Property name="reportMetricsIntervalMillis" required="No" default="30000" sortOrder="3" since="3.1.2">     If 'gatherPerfMetrics' is enabled, how often should they be logged (in ms)?   </Property>   <Property name="maxQuerySizeToLog" required="No" default="2048" sortOrder="4" since="3.1.3">     Controls the maximum length/size of a query that will get logged when profiling or tracing   </Property>   <Property name="packetDebugBufferSize" required="No" default="20" sortOrder="7" since="3.1.3">     The maximum number of packets to retain when 'enablePacketDebug' is true   </Property>   <Property name="slowQueryThresholdMillis" required="No" default="2000" sortOrder="9" since="3.1.2">     If 'logSlowQueries' is enabled, how long should a query (in ms) before it is logged as 'slow'?   </Property>   <Property name="slowQueryThresholdNanos" required="No" default="0" sortOrder="10" since="5.0.7">     If 'useNanosForElapsedTime' is set to true, and this property is set to a non-zero value, the driver will use this threshold (in nanosecond units) to determine if a query was slow.   </Property>   <Property name="useUsageAdvisor" required="No" default="false" sortOrder="10" since="3.1.1">     Should the driver issue 'usage' warnings advising proper and efficient usage of JDBC and MySQL Connector/J to the log (true/false, defaults to 'false')?   </Property>   <Property name="autoGenerateTestcaseScript" required="No" default="false" sortOrder="alpha" since="3.1.9">     Should the driver dump the SQL it is executing, including server-side prepared statements to STDERR?   </Property>   <Property name="autoSlowLog" required="No" default="true" sortOrder="alpha" since="5.1.4">     Instead of using slowQueryThreshold* to determine if a query is slow enough to be logged, maintain statistics that allow the driver to determine queries that are outside the 99th percentile?   </Property>   <Property name="clientInfoProvider" required="No" default="com.mysql.jdbc.JDBC4CommentClientInfoProvider" sortOrder="alpha" since="5.1.0">     The name of a class that implements the com.mysql.jdbc.JDBC4ClientInfoProvider interface in order to support JDBC-4.0's Connection.get/setClientInfo() methods   </Property>   <Property name="dumpMetadataOnColumnNotFound" required="No" default="false" sortOrder="alpha" since="3.1.13">     Should the driver dump the field-level metadata of a result set into the exception message when ResultSet.findColumn() fails?   </Property>   <Property name="dumpQueriesOnException" required="No" default="false" sortOrder="alpha" since="3.1.3">     Should the driver dump the contents of the query sent to the server in the message for SQLExceptions?   </Property>   <Property name="enablePacketDebug" required="No" default="false" sortOrder="alpha" since="3.1.3">     When enabled, a ring-buffer of 'packetDebugBufferSize' packets will be kept, and dumped when exceptions are thrown in key areas in the driver's code   </Property>   <Property name="explainSlowQueries" required="No" default="false" sortOrder="alpha" since="3.1.2">     If 'logSlowQueries' is enabled, should the driver automatically issue an 'EXPLAIN' on the server and send the results to the configured log at a WARN level?   </Property>   <Property name="includeInnodbStatusInDeadlockExceptions" required="No" default="false" sortOrder="alpha" since="5.0.7">     Include the output of "SHOW ENGINE INNODB STATUS" in exception messages when deadlock exceptions are detected?   </Property>   <Property name="logSlowQueries" required="No" default="false" sortOrder="alpha" since="3.1.2">     Should queries that take longer than 'slowQueryThresholdMillis' be logged?   </Property>   <Property name="logXaCommands" required="No" default="false" sortOrder="alpha" since="5.0.5">     Should the driver log XA commands sent by MysqlXaConnection to the server, at the DEBUG level of logging?   </Property>   <Property name="profilerEventHandler" required="No" default="com.mysql.jdbc.profiler.LoggingProfilerEventHandler" sortOrder="alpha" since="5.1.6">     Name of a class that implements the interface com.mysql.jdbc.profiler.ProfilerEventHandler that will be used to handle profiling/tracing events.   </Property>   <Property name="resultSetSizeThreshold" required="No" default="100" sortOrder="alpha" since="5.0.5">     If the usage advisor is enabled, how many rows should a result set contain before the driver warns that it is suspiciously large?   </Property>   <Property name="traceProtocol" required="No" default="false" sortOrder="alpha" since="3.1.2">     Should trace-level network protocol be logged?   </Property>   <Property name="useNanosForElapsedTime" required="No" default="false" sortOrder="alpha" since="5.0.7">     For profiling/debugging functionality that measures elapsed time, should the driver try to use nanoseconds resolution if available (JDK >= 1.5)?   </Property>  </PropertyCategory>  <PropertyCategory name="Miscellaneous">   <Property name="useUnicode" required="No" default="true" sortOrder="0" since="1.1g">     Should the driver use Unicode character encodings when handling strings? Should only be used when the driver can't determine the character set mapping, or you are trying to 'force' the driver to use a character set that MySQL either doesn't natively support (such as UTF-8), true/false, defaults to 'true'   </Property>   <Property name="characterEncoding" required="No" default="" sortOrder="5" since="1.1g">     If 'useUnicode' is set to true, what character encoding should the driver use when dealing with strings? (defaults is to 'autodetect')   </Property>   <Property name="characterSetResults" required="No" default="" sortOrder="6" since="3.0.13">     Character set to tell the server to return results as.   </Property>   <Property name="connectionCollation" required="No" default="" sortOrder="7" since="3.0.13">     If set, tells the server to use this collation via 'set collation_connection'   </Property>   <Property name="useBlobToStoreUTF8OutsideBMP" required="No" default="false" sortOrder="128" since="5.1.3">     Tells the driver to treat [MEDIUM/LONG]BLOB columns as [LONG]VARCHAR columns holding text encoded in UTF-8 that has characters outside the BMP (4-byte encodings), which MySQL server can't handle natively.   </Property>   <Property name="utf8OutsideBmpExcludedColumnNamePattern" required="No" default="" sortOrder="129" since="5.1.3">     When "useBlobToStoreUTF8OutsideBMP" is set to "true", column names matching the given regex will still be treated as BLOBs unless they match the regex specified for "utf8OutsideBmpIncludedColumnNamePattern". The regex must follow the patterns used for the java.util.regex package.   </Property>   <Property name="utf8OutsideBmpIncludedColumnNamePattern" required="No" default="" sortOrder="129" since="5.1.3">     Used to specify exclusion rules to "utf8OutsideBmpExcludedColumnNamePattern". The regex must follow the patterns used for the java.util.regex package.   </Property>   <Property name="loadBalanceEnableJMX" required="No" default="false" sortOrder="2147483647" since="5.1.13">     Enables JMX-based management of load-balanced connection groups, including live addition/removal of hosts from load-balancing pool.   </Property>   <Property name="sessionVariables" required="No" default="" sortOrder="2147483647" since="3.1.8">     A comma-separated list of name/value pairs to be sent as SET SESSION ... to the server when the driver connects.   </Property>   <Property name="useColumnNamesInFindColumn" required="No" default="false" sortOrder="2147483647" since="5.1.7">     Prior to JDBC-4.0, the JDBC specification had a bug related to what could be given as a "column name" to ResultSet methods like findColumn(), or getters that took a String property. JDBC-4.0 clarified "column name" to mean the label, as given in an "AS" clause and returned by ResultSetMetaData.getColumnLabel(), and if no AS clause, the column name. Setting this property to "true" will give behavior that is congruent to JDBC-3.0 and earlier versions of the JDBC specification, but which because of the specification bug could give unexpected results. This property is preferred over "useOldAliasMetadataBehavior" unless you need the specific behavior that it provides with respect to ResultSetMetadata.   </Property>   <Property name="allowNanAndInf" required="No" default="false" sortOrder="alpha" since="3.1.5">     Should the driver allow NaN or +/- INF values in PreparedStatement.setDouble()?   </Property>   <Property name="autoClosePStmtStreams" required="No" default="false" sortOrder="alpha" since="3.1.12">     Should the driver automatically call .close() on streams/readers passed as arguments via set*() methods?   </Property>   <Property name="autoDeserialize" required="No" default="false" sortOrder="alpha" since="3.1.5">     Should the driver automatically detect and de-serialize objects stored in BLOB fields?   </Property>   <Property name="blobsAreStrings" required="No" default="false" sortOrder="alpha" since="5.0.8">     Should the driver always treat BLOBs as Strings - specifically to work around dubious metadata returned by the server for GROUP BY clauses?   </Property>   <Property name="capitalizeTypeNames" required="No" default="true" sortOrder="alpha" since="2.0.7">     Capitalize type names in DatabaseMetaData? (usually only useful when using WebObjects, true/false, defaults to 'false')   </Property>   <Property name="clobCharacterEncoding" required="No" default="" sortOrder="alpha" since="5.0.0">     The character encoding to use for sending and retrieving TEXT, MEDIUMTEXT and LONGTEXT values instead of the configured connection characterEncoding   </Property>   <Property name="clobberStreamingResults" required="No" default="false" sortOrder="alpha" since="3.0.9">     This will cause a 'streaming' ResultSet to be automatically closed, and any outstanding data still streaming from the server to be discarded if another query is executed before all the data has been read from the server.   </Property>   <Property name="compensateOnDuplicateKeyUpdateCounts" required="No" default="false" sortOrder="alpha" since="5.1.7">     Should the driver compensate for the update counts of "ON DUPLICATE KEY" INSERT statements (2 = 1, 0 = 1) when using prepared statements?   </Property>   <Property name="continueBatchOnError" required="No" default="true" sortOrder="alpha" since="3.0.3">     Should the driver continue processing batch commands if one statement fails. The JDBC spec allows either way (defaults to 'true').   </Property>   <Property name="createDatabaseIfNotExist" required="No" default="false" sortOrder="alpha" since="3.1.9">     Creates the database given in the URL if it doesn't yet exist. Assumes the configured user has permissions to create databases.   </Property>   <Property name="emptyStringsConvertToZero" required="No" default="true" sortOrder="alpha" since="3.1.8">     Should the driver allow conversions from empty string fields to numeric values of '0'?   </Property>   <Property name="emulateLocators" required="No" default="false" sortOrder="alpha" since="3.1.0">     Should the driver emulate java.sql.Blobs with locators? With this feature enabled, the driver will delay loading the actual Blob data until the one of the retrieval methods (getInputStream(), getBytes(), and so forth) on the blob data stream has been accessed. For this to work, you must use a column alias with the value of the column to the actual name of the Blob. The feature also has the following restrictions: The SELECT that created the result set must reference only one table, the table must have a primary key; the SELECT must alias the original blob column name, specified as a string, to an alternate name; the SELECT must cover all columns that make up the primary key.   </Property>   <Property name="emulateUnsupportedPstmts" required="No" default="true" sortOrder="alpha" since="3.1.7">     Should the driver detect prepared statements that are not supported by the server, and replace them with client-side emulated versions?   </Property>   <Property name="exceptionInterceptors" required="No" default="" sortOrder="alpha" since="5.1.8">     Comma-delimited list of classes that implement com.mysql.jdbc.ExceptionInterceptor. These classes will be instantiated one per Connection instance, and all SQLExceptions thrown by the driver will be allowed to be intercepted by these interceptors, in a chained fashion, with the first class listed as the head of the chain.   </Property>   <Property name="functionsNeverReturnBlobs" required="No" default="false" sortOrder="alpha" since="5.0.8">     Should the driver always treat data from functions returning BLOBs as Strings - specifically to work around dubious metadata returned by the server for GROUP BY clauses?   </Property>   <Property name="generateSimpleParameterMetadata" required="No" default="false" sortOrder="alpha" since="5.0.5">     Should the driver generate simplified parameter metadata for PreparedStatements when no metadata is available either because the server couldn't support preparing the statement, or server-side prepared statements are disabled?   </Property>   <Property name="ignoreNonTxTables" required="No" default="false" sortOrder="alpha" since="3.0.9">     Ignore non-transactional table warning for rollback? (defaults to 'false').   </Property>   <Property name="jdbcCompliantTruncation" required="No" default="true" sortOrder="alpha" since="3.1.2">     Should the driver throw java.sql.DataTruncation exceptions when data is truncated as is required by the JDBC specification when connected to a server that supports warnings (MySQL 4.1.0 and newer)? This property has no effect if the server sql-mode includes STRICT_TRANS_TABLES.   </Property>   <Property name="loadBalanceAutoCommitStatementRegex" required="No" default="" sortOrder="alpha" since="5.1.15">     When load-balancing is enabled for auto-commit statements (via loadBalanceAutoCommitStatementThreshold), the statement counter will only increment when the SQL matches the regular expression.  By default, every statement issued matches.   </Property>   <Property name="loadBalanceAutoCommitStatementThreshold" required="No" default="0" sortOrder="alpha" since="5.1.15">     When auto-commit is enabled, the number of statements which should be executed before triggering load-balancing to rebalance.  Default value of 0 causes load-balanced connections to only rebalance when exceptions are encountered, or auto-commit is disabled and transactions are explicitly committed or rolled back.   </Property>   <Property name="loadBalanceBlacklistTimeout" required="No" default="0" sortOrder="alpha" since="5.1.0">     Time in milliseconds between checks of servers which are unavailable.   </Property>   <Property name="loadBalanceConnectionGroup" required="No" default="" sortOrder="alpha" since="5.1.13">     Logical group of load-balanced connections within a classloader, used to manage different groups independently.  If not specified, live management of load-balanced connections is disabled.   </Property>   <Property name="loadBalanceExceptionChecker" required="No" default="com.mysql.jdbc.StandardLoadBalanceExceptionChecker" sortOrder="alpha" since="5.1.13">     Fully-qualified class name of custom exception checker.  The class must implement com.mysql.jdbc.LoadBalanceExceptionChecker interface, and is used to inspect SQLExceptions and determine whether they should trigger fail-over to another host in a load-balanced deployment.   </Property>   <Property name="loadBalancePingTimeout" required="No" default="0" sortOrder="alpha" since="5.1.13">     Time in milliseconds to wait for ping response from each of load-balanced physical connections when using load-balanced Connection.   </Property>   <Property name="loadBalanceSQLExceptionSubclassFailover" required="No" default="" sortOrder="alpha" since="5.1.13">     Comma-delimited list of classes/interfaces used by default load-balanced exception checker to determine whether a given SQLException should trigger failover.  The comparison is done using Class.isInstance(SQLException) using the thrown SQLException.   </Property>   <Property name="loadBalanceSQLStateFailover" required="No" default="" sortOrder="alpha" since="5.1.13">     Comma-delimited list of SQLState codes used by default load-balanced exception checker to determine whether a given SQLException should trigger failover.  The SQLState of a given SQLException is evaluated to determine whether it begins with any value in the comma-delimited list.   </Property>   <Property name="loadBalanceValidateConnectionOnSwapServer" required="No" default="false" sortOrder="alpha" since="5.1.13">     Should the load-balanced Connection explicitly check whether the connection is live when swapping to a new physical connection at commit/rollback?   </Property>   <Property name="maxRows" required="No" default="-1" sortOrder="alpha" since="all versions">     The maximum number of rows to return (0, the default means return all rows).   </Property>   <Property name="netTimeoutForStreamingResults" required="No" default="600" sortOrder="alpha" since="5.1.0">     What value should the driver automatically set the server setting 'net_write_timeout' to when the streaming result sets feature is in use? (value has unit of seconds, the value '0' means the driver will not try and adjust this value)   </Property>   <Property name="noAccessToProcedureBodies" required="No" default="false" sortOrder="alpha" since="5.0.3">     When determining procedure parameter types for CallableStatements, and the connected user  can't access procedure bodies through "SHOW CREATE PROCEDURE" or select on mysql.proc  should the driver instead create basic metadata (all parameters reported as IN VARCHARs, but allowing registerOutParameter() to be called on them anyway) instead  of throwing an exception?   </Property>   <Property name="noDatetimeStringSync" required="No" default="false" sortOrder="alpha" since="3.1.7">     Don't ensure that ResultSet.getDatetimeType().toString().equals(ResultSet.getString())   </Property>   <Property name="noTimezoneConversionForTimeType" required="No" default="false" sortOrder="alpha" since="5.0.0">     Don't convert TIME values using the server timezone if 'useTimezone'='true'   </Property>   <Property name="nullCatalogMeansCurrent" required="No" default="true" sortOrder="alpha" since="3.1.8">     When DatabaseMetadataMethods ask for a 'catalog' parameter, does the value null mean use the current catalog? (this is not JDBC-compliant, but follows legacy behavior from earlier versions of the driver)   </Property>   <Property name="nullNamePatternMatchesAll" required="No" default="true" sortOrder="alpha" since="3.1.8">     Should DatabaseMetaData methods that accept *pattern parameters treat null the same as '%' (this is not JDBC-compliant, however older versions of the driver accepted this departure from the specification)   </Property>   <Property name="overrideSupportsIntegrityEnhancementFacility" required="No" default="false" sortOrder="alpha" since="3.1.12">     Should the driver return "true" for DatabaseMetaData.supportsIntegrityEnhancementFacility() even if the database doesn't support it to workaround applications that require this method to return "true" to signal support of foreign keys, even though the SQL specification states that this facility contains much more than just foreign key support (one such application being OpenOffice)?   </Property>   <Property name="padCharsWithSpace" required="No" default="false" sortOrder="alpha" since="5.0.6">     If a result set column has the CHAR type and the value does not fill the amount of characters specified in the DDL for the column, should the driver pad the remaining characters with space (for ANSI compliance)?   </Property>   <Property name="pedantic" required="No" default="false" sortOrder="alpha" since="3.0.0">     Follow the JDBC spec to the letter.   </Property>   <Property name="pinGlobalTxToPhysicalConnection" required="No" default="false" sortOrder="alpha" since="5.0.1">     When using XAConnections, should the driver ensure that operations on a given XID are always routed to the same physical connection? This allows the XAConnection to support "XA START ... JOIN" after "XA END" has been called   </Property>   <Property name="populateInsertRowWithDefaultValues" required="No" default="false" sortOrder="alpha" since="5.0.5">     When using ResultSets that are CONCUR_UPDATABLE, should the driver pre-populate the "insert" row with default values from the DDL for the table used in the query so those values are immediately available for ResultSet accessors? This functionality requires a call to the database for metadata each time a result set of this type is created. If disabled (the default), the default values will be populated by the an internal call to refreshRow() which pulls back default values and/or values changed by triggers.   </Property>   <Property name="processEscapeCodesForPrepStmts" required="No" default="true" sortOrder="alpha" since="3.1.12">     Should the driver process escape codes in queries that are prepared?   </Property>   <Property name="queryTimeoutKillsConnection" required="No" default="false" sortOrder="alpha" since="5.1.9">     If the timeout given in Statement.setQueryTimeout() expires, should the driver forcibly abort the Connection instead of attempting to abort the query?   </Property>   <Property name="relaxAutoCommit" required="No" default="false" sortOrder="alpha" since="2.0.13">     If the version of MySQL the driver connects to does not support transactions, still allow calls to commit(), rollback() and setAutoCommit() (true/false, defaults to 'false')?   </Property>   <Property name="retainStatementAfterResultSetClose" required="No" default="false" sortOrder="alpha" since="3.1.11">     Should the driver retain the Statement reference in a ResultSet after ResultSet.close() has been called. This is not JDBC-compliant after JDBC-4.0.   </Property>   <Property name="rollbackOnPooledClose" required="No" default="true" sortOrder="alpha" since="3.0.15">     Should the driver issue a rollback() when the logical connection in a pool is closed?   </Property>   <Property name="runningCTS13" required="No" default="false" sortOrder="alpha" since="3.1.7">     Enables workarounds for bugs in Sun's JDBC compliance testsuite version 1.3   </Property>   <Property name="serverTimezone" required="No" default="" sortOrder="alpha" since="3.0.2">     Override detection/mapping of timezone. Used when timezone from server doesn't map to Java timezone   </Property>   <Property name="statementInterceptors" required="No" default="" sortOrder="alpha" since="5.1.1">     A comma-delimited list of classes that implement "com.mysql.jdbc.StatementInterceptor" that should be placed "in between" query execution to influence the results. StatementInterceptors are "chainable", the results returned by the "current" interceptor will be passed on to the next in in the chain, from left-to-right order, as specified in this property.   </Property>   <Property name="strictFloatingPoint" required="No" default="false" sortOrder="alpha" since="3.0.0">     Used only in older versions of compliance test   </Property>   <Property name="strictUpdates" required="No" default="true" sortOrder="alpha" since="3.0.4">     Should the driver do strict checking (all primary keys selected) of updatable result sets (true, false, defaults to 'true')?   </Property>   <Property name="tinyInt1isBit" required="No" default="true" sortOrder="alpha" since="3.0.16">     Should the driver treat the datatype TINYINT(1) as the BIT type (because the server silently converts BIT -> TINYINT(1) when creating tables)?   </Property>   <Property name="transformedBitIsBoolean" required="No" default="false" sortOrder="alpha" since="3.1.9">     If the driver converts TINYINT(1) to a different type, should it use BOOLEAN instead of BIT for future compatibility with MySQL-5.0, as MySQL-5.0 has a BIT type?   </Property>   ____________________________________________________________________ He quitado un poco de texto... Saludos y gracias!! Debe ser una tontería pero como novato en java no caigo.

Buenas,

Primero hice la interfaz, y después la clase para la conexión. En la clase llegue a poner solo el siguiente código:

____________________________________________________________________

package PackAplicaJDBC;

import java.sql.*;

public class DBManagement {
   
   private final String drv = "";
   private final String db = "";
   private final String userpass = "";
   
   private Statement st;
   private Connection conectar;
   
   public DBManagement(){
      
   }
   
   public Statement getSt(){
      return st;
   }
}

_________________________________________________________________

Solo puse eso y lo ejecute por ver como quedaba la interfaz. Yo creo que el problema puede surgir cuando se crea "public Statement getST(){}", cuando no se importa nada al principio el  compilador da la opción de elegir lo que se necesita importar... y a lo mejor jajaj solo a lo mejor hay esta el problema. En el ejemplo que me salió bien importe todo manualmente sin utilizar las opciones que da el compilador. Lo raro es que cuando elimino en el proyecto la librería y el código de la clase de conexiones se produce otro error:

Could no find the main class:
com.mysql.jbdc.DocsConnectionPropsHelper. Program will exit.

Y bueno ahora solo afecta al proyecto, pero hace algún tiempo afectaba a todos los proyectos, y me vi obligado a volver a instalar el compilador... Pero bueno ahora solo afecta al proyecto.

La librería la eliminado "remove", desde el mismo lugar donde la añadí para hacerlo de la "mejor" forma posible... pero nada.

Muchas gracias, a ver si os suena a algo. Debe ser algo básico lo que esta pasando pero no caigo. Saludos.

Buenas! No he encontrado la solución a este problema. He tenido que eliminar el eclipse y volver a ponerlo. He hecho otro ejemplo y no me ha surgido el problema, la diferencia esta en que todo el código lo he introducido en vez de utilizar las opciones que te da eclipse para importar clases o para llamar a métodos de la librería "mysql-connector-java" . De alguna manera de esta forma no se genera ningún problema interno. Debe ser que en algún archivo se queda relaciona con la librería, y si después se comete algún error hay que ir al archivo de alguna forma...

Saludos!