Spring JDBC error connection

I use Tomcat with Spring (with web services Jersey async) and i set a pool connection in Tomcat like this:

<Resource auth="Container" driverClassName="com.mysql.jdbc.Driver"
    maxActive="100" maxIdle="50" maxWait="10000" name="jdbc/UsersDB"
    password="secret" type="javax.sql.DataSource"  url="jdbc:mysql://localhost:3306/DB"
    username="root" />

In my JDBC class for example i have:

    public String getMFromToken(String token) {

    logger.info(TAG_LOG + " "
            + "prima della richiesta JDBC id" );

    int id = jdbcTemplateObject.queryForObject(sqlGetToken, new Object [] {token}, Integer.class);

    logger.info(TAG_LOG + " "
            + "recuperato id " + id );

    String sqlGetMFromCred = "select matricola from stud where cred_id = ?";

    logger.info(TAG_LOG + " "
            + "prima della richiesta JDBC matricola" );

    String matricola = jdbcTemplateObject.queryForObject(sqlGetMFromCred, new Object [] {id},String.class);

    logger.info(TAG_LOG + " "
            + "recuperata matricola " + matricola );

    return matricola;
}

If I do not do requests (requests that require a query to the database) to tomcat for a long time, tomcat response me a 500 error, but if i call any requests (requests not require a query to the db) all works.

So the problem is some configuration of Spring (i think)..Why Spring not work if i wait long time to do any request ?

sorry for my bad english