Get list of all Buckets

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import org.apache.http.HttpStatus;

public class ServiceOperations {
	
		/*
	 	 * This program fetches list of all buckets
		 * @param serverURL: URL of S3 Compatible REST server(http://<S3 server IP> : <S3 server port> /queryio/). For example: http://192.168.0.1:5667/queryio/
		 * @param token: authorization token.
		 */
	public void getService(String serverURL, String token) throws Exception {
		URL url = null;
		HttpURLConnection httpCon = null;
		InputStream is = null;
		try {
			/* append "/" at end of serverURL */
			if (!serverURL.endsWith("/")) {
				serverURL = serverURL + "/";
			}	
			url = new URL(serverURL);	//URL object with serverURL

			//Returns a URLConnection object that represents a connection to the remote object referred to by the URL.
			httpCon = (HttpURLConnection) url.openConnection();

			httpCon.setDoOutput(true);	// to use the URL connection for output
			httpCon.setRequestMethod("GET");	//GET request is used.

			httpCon.setRequestProperty("authorization", token);	//Provides token for authorization

			httpCon.connect();	//Opens a communications link to the resource reference by the URL

			if (httpCon.getResponseCode() == HttpStatus.SC_OK) {	//Check for OK response code
				is = httpCon.getInputStream();
				// Process response here
				StringWriter writer = new StringWriter();                 
				IOUtils.copy(is, writer, "UTF-8");                 
				System.out.println(writer.toString());	//Displaying response
			}
		} finally {
			try {
				if (is != null)
					is.close();	//close InputStream
			} catch (IOException e) {
				e.printStackTrace();
			}
			if (httpCon != null) {
				httpCon.disconnect();	//disconnect connection	
			}
		}
	}
}