writeProxyPoolToFile

 import com.screenscraper.util.*;

 // Create a new ProxyServerPool object.
 proxyServerPool = new ProxyServerPool();

 // Must be set on the session before other calls are made
 session.setProxyServerPool(proxyServerPool);

 // This tells the pool to populate itself from a file
 proxyServerPool.populateFromFile( "proxies.txt" );

 // Validate proxies up to 25 proxies at a time.
 proxyServerPool.setNumProxiesToValidateConcurrently( 25 );

 // Set timout interval
 proxyServerPool.filter( 7 );

 // Once filtering is done, it's often helpful to write the good
 // set of proxies out to a file. That way you may not have to
 // filter again the next time.

 proxyServerPool.writeProxyPoolToFile( "good_proxies.txt" );