Java Apache HttpClient代理问题

我正在尝试执行一项任务，以便向服务器获取一些参数。我从stackoverflow得到这个例子，我面临一个奇怪的错误。有人能帮我解开这个谜团吗？附件是我正在使用的类文件

import java.io.IOException;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.auth.AuthScope;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.params.ConnRoutePNames;
import org.apache.http.impl.client.DefaultHttpClient;

public class HttpClientTest {
     private static final String PROXY_HOST = "proxy.domain";
     private static final int PROXY_PORT = 8080;

    public static void main(String[] args) {

    try{
      String username = "username";
      String password = "Password";
      DefaultHttpClient httpclient = new DefaultHttpClient();
      org.apache.http.auth.Credentials credentials_new = new      org.apache.http.auth.UsernamePasswordCredentials(username, password) ;

      CredentialsProvider cp = httpclient.getCredentialsProvider();
      cp.setCredentials(new AuthScope(PROXY_HOST, PROXY_PORT),credentials_new);
      HttpHost proxy = new HttpHost(PROXY_HOST, PROXY_PORT);
      httpclient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);
      HttpGet httpget = new HttpGet("http://www.google.com");
      HttpResponse response = httpclient.execute(httpget);


      System.out.println("Response: " + response.getStatusLine());
  } catch (ClientProtocolException e1) {
    e1.printStackTrace();
  } catch (IOException e1) {
        e1.printStackTrace();
  }
 }
}

我得到的错误是

Exception in thread "main" java.lang.NoSuchMethodError: org.apache.commons.codec.binary.Base64.<init>(I)V
at org.apache.http.impl.auth.GGSSchemeBase.<init>(GGSSchemeBase.java:75)
at org.apache.http.impl.auth.SPNegoScheme.<init>(SPNegoScheme.java:47)
at org.apache.http.impl.auth.SPNegoSchemeFactory.newInstance(SPNegoSchemeFactory.java:55)
at org.apache.http.auth.AuthSchemeRegistry.getAuthScheme(AuthSchemeRegistry.java:114)
at org.apache.http.impl.client.AuthenticationStrategyImpl.select(AuthenticationStrategyImpl.java:180)
at org.apache.http.impl.client.HttpAuthenticator.authenticate(HttpAuthenticator.java:144)
at org.apache.http.impl.client.DefaultRequestDirector.handleResponse(DefaultRequestDirector.java:1085)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:548)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:784)
at HttpClientTest.main(HttpClientTest.java:36)

线程“main”java.lang.NoSuchMethodError中的异常：org.apache.commons.codec.binary.Base64。（I）V 位于org.apache.http.impl.auth.GGSSchemeBase。（GGSSchemeBase.java:75） 位于org.apache.http.impl.auth.SPNegoScheme（SPNegoScheme.java:47） 位于org.apache.http.impl.auth.SPNegoSchemeFactory.newInstance（SPNegoSchemeFactory.java:55） 在org.apache.http.auth.AuthSchemeRegistry.getAuthScheme（AuthSchemeRegistry.java:114）上 位于org.apache.http.impl.client.AuthenticationStrategyImpl.select（AuthenticationStrategyImpl.java:180） 位于org.apache.http.impl.client.HttpAuthenticator.authenticate（HttpAuthenticator.java:144） 位于org.apache.http.impl.client.DefaultRequestDirector.HandlerResponse（DefaultRequestDirector.java:1085） 位于org.apache.http.impl.client.DefaultRequestDirector.execute（DefaultRequestDirector.java:548） 位于org.apache.http.impl.client.AbstractHttpClient.execute（AbstractHttpClient.java:906） 位于org.apache.http.impl.client.AbstractHttpClient.execute（AbstractHttpClient.java:805） 位于org.apache.http.impl.client.AbstractHttpClient.execute（AbstractHttpClient.java:784） 位于HttpClientTest.main（HttpClientTest.java:36） 非常感谢

类路径中需要1.4或更高版本

此库包含Base64实现

Exception in thread "main" java.lang.NoSuchMethodError: org.apache.commons.codec.binary.Base64.<init>(I)V

线程“main”java.lang.NoSuchMethodError中的异常：org.apache.commons.codec.binary.Base64。（I）V

---

路径中有一个旧的编解码器jar。刚换上最新的，一切正常。非常感谢@Jarandinor