我的应用程序使用Oracle UCP监听少数表。在正式生产环境中，应用程序工作正常，但在测试环境中，应用程序从池中耗尽连接。我也在每个查询中关闭并返回使用过的连接。请参考连接关闭方法。

public static synchronized void closeConnection(Connection con) throws Exception {
    String print;
    try {
        if (con != null && !con.isClosed()) {
            con.close();
            con =null;
            Config.DB_POOL_COUNT_AVAILABLE = pds.getAvailableConnectionsCount();
            Config.DB_POOL_COUNT_BUSSY = pds.getBorrowedConnectionsCount();
            Config.DB_POOL_COUNT_OPENED = Config.DB_POOL_COUNT_AVAILABLE + Config.DB_POOL_COUNT_BUSSY;      
        } else {
            Config.DB_POOL_COUNT_AVAILABLE = pds.getAvailableConnectionsCount();
            Config.DB_POOL_COUNT_BUSSY = pds.getBorrowedConnectionsCount();
            Config.DB_POOL_COUNT_OPENED = Config.DB_POOL_COUNT_AVAILABLE + Config.DB_POOL_COUNT_BUSSY;              
        }
    } catch (Exception e) {
        Logger.errorLog(e);
    } finally {
        Config.DB_POOL_COUNT_AVAILABLE = pds.getAvailableConnectionsCount();
        Config.DB_POOL_COUNT_BUSSY = pds.getBorrowedConnectionsCount();
        Config.DB_POOL_COUNT_OPENED = Config.DB_POOL_COUNT_AVAILABLE + Config.DB_POOL_COUNT_BUSSY;  
        if(con != null && !con.isClosed()){
            con.close();
            con=null;
        } 
    }       
}