MemoryMonitor demonstrates the use of the java.lang.management API in observing the memory usage of all memory pools consumed by the application. This simple demo program queries the memory usage of each memory pool and plots the memory u

DBCP(DataBase connection pool),数据库连接池。由于建立数据库连接是一个非常耗时耗资源的行为，所以通过连接池预先同数据库建立一些连接，放在内存中，应用程序需要建立数据库连接时直接到连接池中申请一个就行，用完后再放回去。-DBCP (DataBase connection pool), the database connection pool. Since the establishment of a database connection is a very time