public static synchronized JdbcConnectionPools getInstance(JdbcConnectionPoolFactory jdbcConnectionPoolFactory) {
        if (instance == null) {
            jdbcConnectionPoolFactory = jdbcConnectionPoolFactory;
            instance = new JdbcConnectionPools();
        }
        return instance;
    }
A Jdbc Connection pools implementation.
Copy from com.ververica:flink-cdc-base:2.3.0.
inlong-sort/sort-flink/cdc-base/src/main/java/org/apache/inlong/sort/cdc/base/relational/connection/JdbcConnectionPools.java