Problem with call static methods in plugin

How to call C# to java?

I find some method in website but it not work.

Here is my c# script

 var activityJavaClass=new AndroidJavaClass("com.unity3d.player.UnityPlayer");
  if(activityJavaClass!=null){
  Debug.Log("UnityPlayer class not null");
                             // To get the activity
 var currentActivityJavaObject=activityJavaClass.GetStatic<AndroidJavaObject>("currentActivity");
 AndroidJavaObject app = currentActivityJavaObject.Call<AndroidJavaObject>("getApplicationContext");
  
  if(currentActivityJavaObject!=null){
 Debug.Log("currentActivity object of UnityPlayer not null");
 var manager=GetComponent<CapturedScreenManager>()as CapturedScreenManager;
  
 if(manager!=null){
                                     //string path="/storage/emulated/0/DCIM/Camera/VID_20151017_072913.mp4";
 string path=manager.androidSavePath;
 if(path==null|| string.Equals(path,"")){
  Debug.LogError("Android save path is null or empty");
 return;
 }
                                     Debug.Log("About to share to Youku from path: " + path);
                                     // To get the share video class
                                     AndroidJavaClass javaClass=new AndroidJavaClass("com.youku.uploader.ShareToYouku");
  
 if(javaClass!=null){
 Debug.Log ("ShareToYouku java class not null");
 currentActivityJavaObject.Call("runOnUiThread", new AndroidJavaRunnable(() =>{
 javaClass.CallStatic("GetDataFromUnity", new object[]{ "32e7028d0a42009c","50cc4b8cfe70fd56ccdfecd7460e88b5",accessToken,title,tag, path, app});
                                         }));
                                     }else{
                                         Debug.LogError("ShareToYouku java class is null");
                                     }
                                 }else{
                                     Debug.LogError("Captured screen manager is null");
                                 }
                             }else {
                                 Debug.LogError("currentActivity object of UnityPlayer is null");
                             }
                         }else{
                             Debug.LogError("UnityPlayer class is null");
                         }

Here is my java script

  public static void GetDataFromUnity(String clientID,String client_secret,String access_token, String title, String tags, String file_name, Context context)

I already add jar into Plugin>Android. But it show error after the Debug Log (ShareToYouku java class not null)

 11-10 13:02:10.466: I/Unity(3354): AndroidJavaException: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.youku.uploader.YoukuUploader.upload(java.util.HashMap, java.util.HashMap, com.youku.uploader.IUploadResponseHandler)' on a null object reference
 11-10 12:05:45.585: I/Unity(20610):   at UnityEngine._AndroidJNIHelper.GetSignature (System.Object obj) [0x00000] in <filename unknown>:0
 11-10 12:06:48.950: I/Unity(20610):   at UnityEngine._AndroidJNIHelper.GetSignature (System.Object[] args) [0x00000] in <filename unknown>:0
 11-10 12:06:48.950: I/Unity(20610):   at UnityEngine._AndroidJNIHelper.GetMethodID (IntPtr jclass, System.String methodName, System.Object[] args, Boolean isStatic) [0x00000] in <filename unknown>:0
 11-10 12:06:48.950: I/Unity(20610):   at UnityEngine.AndroidJNIHelper.GetMethodID (IntPtr jclass, System.String methodName, System.Object[] args, Boolean isStatic) [0x00000] in <filename unknown>:0
 11-10 12:07:56.735: I/Unity(20610):   at UnityEngine.AndroidJavaObject._CallStatic (System.String methodName, System.Object[] args) [0x00000] in <filename unknown>:0
 11-10 12:07:56.735: I/Unity(20610):   at UnityEngine.AndroidJavaObject.CallStatic (System.String methodName, System.Object[] args) [0x00000] in <filename unknown>:0
 11-10 12:07:56.735: I/Unity(20610):   at UIButtonShare+<GetAccessToken>c__AnonStorey39+<GetAccessToken>c__AnonStorey36.<>m__60 () [0x00000] in <f