question: public PersistedQueue ( final File queueEnvPath , final String queueName , final int cacheSize ) { queueEnvPath . mkdirs ( ) ; final EnvironmentConfig dbEnvConfig = new EnvironmentConfig ( ) ; dbEnvConfig . setTransactional ( false ) ; dbEnvConfig . setAllowCreate ( true ) ; this . dbEnv = new Environment ( queueEnvPath , dbEnvConfig ) ; DatabaseConfig dbConfig = new DatabaseConfig ( ) ; dbConfig . setTransactional ( false ) ; dbConfig . setAllowCreate ( true ) ; dbConfig . setDeferredWrite ( true ) ; this . queueDatabase = dbEnv . openDatabase ( null , queueName , dbConfig ) ; this . queueName = queueName ; this . cacheSize = cacheSize ; this . opsCounter = 0 ; }
target:  Creates instance of persistent queue.