abstract public CacheResponse get(URI uri,
    String rqstMethod,
    Map rqstHeaders) throws IOException
Retrieve the cached response based on the requesting uri,
request method and request headers. Typically this method is
called by the protocol handler before it sends out the request
to get the network resource. If a cached response is returned,
that resource is used instead.

 public static synchronized ResponseCache getDefault() 
{
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(SecurityConstants.GET_RESPONSECACHE_PERMISSION);
        }
        return theResponseCache;
}

Gets the system-wide response cache.

 abstract public CacheRequest put(URI uri,
    URLConnection conn) throws IOException
The protocol handler calls this method after a resource has
been retrieved, and the ResponseCache must decide whether or
not to store the resource in its cache. If the resource is to
be cached, then put() must return a CacheRequest object which
contains an OutputStream that the protocol handler will
use to write the resource into the cache. If the resource is
not to be cached, then put must return null.

 public static synchronized  void setDefault(ResponseCache responseCache) 
{
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(SecurityConstants.SET_RESPONSECACHE_PERMISSION);
        }
        theResponseCache = responseCache;
}

Sets (or unsets) the system-wide cache. Note: non-standard procotol handlers may ignore this setting.