JDBC Connection pool not reopening connections in Tomcat

Try adding a validation query attribute. This should have the effect of automatically closing and re-opening the connection after a timeout like this:

validationQuery="SELECT 1"

First, get rid of the autoReconnect property. You don't need this with a connection pool and may cause problems.

Second, ensure that you close all resources (Connection, Statement and ResultSet) in your JDBC code in the finally block.

I am not sure if this applies in your case, but a common misconception among starters is that they seem to think that you don't need to close those resources in case of a pooled connections. This is untrue. A pooled connection is a wrapper (decorator) around a connection which has a slightly changed close() method which roughly look like

public void close() throws SQLException {
    if (this.connection is still active) {
        do not close this.connection, but just return it to pool for reuse;
    } else {
        actually invoke this.connection.close();
    }
}

With other words, closing them frees up the pooled connection so that it can be put back in the pool for future reuse. If you acquire connections without closing them, then the pool will run out of connections sooner or later.