Language_suport and Other Language-Oriented API: strings,exceptions, threads, #java.lang.* offers the String class to suport strings, the Throwable class to suport exceptions,and the Thread class and Runnable inteface to suport threads.what's more, StringBuffer for creating changeable strings, a Math class for performing operations about math...
Collections-Oriented APIS:#java.util.*,Collections and Arrays classed provide some static methods to deal with the problems about Collections and arrays
Additonal Utility APIS：Concurrency Utilities framework,#java.util.concurrent,java.util.conrrent.atomic,java.util.conrrent.locks; what'smore,java.util package also provide the Date class,Formatter class, the Random class and the Scanner class,#java.util.zip, java.util.jar
Classic I/O APIS:#java.io.*\
Networking APIs:preform I/O over a network,#java.net.*,Socket and ServerSocket class to create the client and server ends of network communication link,URL class,CookiePolicy and CookieManager
New I/O APIs:sophisticated I/O mechanisms such as menory-mapping,readiness selection via Buffer, Channel,Selector and related types found in #java.nio and related packages,also# java.util.regex suports new I/O by offering high-performance string operations
