I am new to JNI. And have a few questions : Can JNI handle every type dll exists in windows? I wanted to link a library but it gives me error. Is it possible JNI and the dll are not compatible?

Excerpt from VB .NET (It works)

Private Declare Function ConnectReader Lib "rfidhid.dll" () As Integer
Private Declare Function DisconnectReader Lib "rfidhid.dll" () As Integer
Private Declare Function SetAntenna Lib "rfidhid.dll" (ByVal mode As Integer) As Integer

Full Code From Java

public class MainForm {

/**
 * @param args
 */
public native int ConnectReader();
public static void main(String[] args) {
    // TODO Auto-generated method stub

    MainForm mf = new MainForm();

    System.out.println(mf.ConnectReader());
}

static {
  System.loadLibrary("rfidhid");
}

}

Error code shown

Exception in thread "main" java.lang.UnsatisfiedLinkError: MainForm.ConnectReader()I
at MainForm.ConnectReader(Native Method)
at MainForm.main(MainForm.java:13)

Can anyone point to me where I might do wrong