NoSuchMethod获取gdata服务时出错

Question

我收到以下错误:

Exception in thread "main" java.lang.NoSuchMethodError: com.google.common.collect.ImmutableSet.of([Ljava/lang/Object;)Lcom/google/common/collect/ImmutableSet;
at com.google.gdata.wireformats.AltFormat$Builder.setAcceptableTypes(AltFormat.java:399)
at com.google.gdata.wireformats.AltFormat$Builder.setAcceptableXmlTypes(AltFormat.java:387)
at com.google.gdata.wireformats.AltFormat.<clinit>(AltFormat.java:49)
at com.google.gdata.client.Service.<clinit>(Service.java:558)
at testproject.TestProject.run(TestProject.java:22)
at testproject.TestProject.main(TestProject.java:31)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

这来自以下代码:

package testproject;

import com.google.gdata.client.youtube.YouTubeService;
import com.google.gdata.util.*;
import java.util.logging.*;

public class TestProject {

  public static void main(String[] args) {
    try {
      YouTubeService service = new YouTubeService("Test", "developerKey");
      service.setUserCredentials("root@gmail.com", "pa$$word");
    } catch (AuthenticationException ex) {
      Logger.getLogger(TestProject.class.getName()).log(Level.SEVERE, null, ex);
    }
  }
}

起初,我在http://code.google.com/p/gdata-java-client/downloads/list中包含了每个库,并且还导入了比我需要的更多的库.我已经删除了我认为不必要的库(感谢thinksteep).所以我目前包含的库是以下库:

mail.jar
activation.jar
ant.jar
gdata-core-1.0.jar
gdata-media-1.0.jar
guava-11.0.1.jar
gdata-youtube-2.0.jar
gdata-youtube-met-2.0.jar

(可能有一些库是没有必要的...但我现在已经结束......)我只是想测试一下YouTube服务,这样我就能搞定这个项目,但是没有骰子.哦,我还包括这个库:http://code.google.com/p/guava-libraries,因为在我收到NoClassDefFound错误之前,包括该库似乎解决了它.提前感谢您的帮助!哦,我也在gdata 入门指南中完全遵循了每一步(或者至少我是这么认为).我的测试版本在最后成功了...再次感谢!

Answer 1

添加超过要求可能也会引起问题.java.lang.NoSuchMethodError如果运行时找不到具有精确签名的必需方法,则通常会发生错误.可能的原因是:

1) There might be mulitple jars with same code, which may cause wrong class get loaded.

2) Incompatable version of jar, the jar you have in classpath might be older version/newer version.

确保没有发生这种情况.