question: public static void init ( Properties conf ) { if ( conf . containsKey ( "db.driver" ) ) { DRIVER = conf . getProperty ( "db.driver" ) ; } if ( conf . containsKey ( "db.url" ) ) { URL = conf . getProperty ( "db.url" ) ; } if ( conf . containsKey ( "db.number" ) ) { MAX_ACTIVE_NUMBER = Integer . parseInt ( conf . getProperty ( "db.number" ) ) ; } if ( conf . containsKey ( "db.validation.sql" ) ) { VALIDATION_SQL = conf . getProperty ( "db.validation.sql" ) ; } ds = new BasicDataSource ( ) ; ds . setDriverClassName ( DRIVER ) ; ds . setUrl ( URL ) ; if ( USER != null ) ds . setUsername ( USER ) ; if ( PASSWD != null ) ds . setPassword ( PASSWD ) ; ds . setMaxActive ( MAX_ACTIVE_NUMBER ) ; ds . setMaxIdle ( MAX_ACTIVE_NUMBER ) ; ds . setMaxWait ( MAX_WAIT_TIME ) ; ds . setDefaultAutoCommit ( true ) ; ds . setDefaultReadOnly ( false ) ; ds . setValidationQuery ( null ) ; ds . setPoolPreparedStatements ( true ) ; }
target:  initialize the DB object by the configuration.