How to get USB storage path? - android-studio

Question

I am trying to read the data in a text file inside my USB OTG storage but I am not able to do it as I am new to Android development. Can anyone guide me with the process?
I tried the following library and implemented in a simple method:
This library
This is my code:
package com.numerologysolution.usbplugin;
import com.faraji.environment3.Device;
import com.faraji.environment3.Environment3;
public class HelloWorld {
public static Device[] usb()
{
Device[] devices = Environment3.getDevices(null, true, true, false);
return devices;
}
}
It says Invalid response from JNI
This is my JNI code:
numerologysolution.Jni.JNIUtil.StaticCall("usb", "Invalid Response From JNI", "com.numerologysolution.usbplugin.HelloWorld");
This is JNI class I created:
namespace numerologysolution.Jni
{
public class JNIUtil
{
public static T StaticCall<T>(string methodName, T defaultValue, string androidJavaClass)
{
T result;
// Only works on Android!
if (Application.platform != RuntimePlatform.Android)
{
return defaultValue;
}
try
{
using (AndroidJavaClass androidClass = new AndroidJavaClass(androidJavaClass))
{
if (null != androidClass)
{
result = androidClass.CallStatic<T>(methodName);
}
else
{
result = defaultValue;
}
}
}
catch (System.Exception ex)
{
// If there is an exception, do nothing but return the default value
// Uncomment this to see exceptions in Unity Debug Log....
// UnityEngine.Debug.Log(string.Format("{0}.{1} Exception:{2}", androidJavaClass, methodName, ex.ToString() ));
return defaultValue;
}
return result;
}
}
}
Can anyone guide me in the right direction regarding this?
Thanks in advance.