Ecplise Java JNI, java.lang.UnsatisfiedLinkError loading dll

I'm having a problem with loading printer dll. I have a dll file from the printer manufacturer (JniPrinterStatusLib.dll). I wrote code like printer manufacturer suggested. The code is:

package com.printer.test

public class JniPrinterStatus {
    static{
        System.loadLibrary("JniPrinterStatusLib");
    }

    public native int GetStatus(String printer);
}

package com.printer.test

public class TestSample {
    public static void main(String[] args) {
        int status;
        String printer = "MY PRINTER";
        JniPrinterStatus jps = new JniPrinterStatus();

        System.out.println("PRINTER NAME = " + printer);

        status = jps.GetStatus(printer);
        if (status == -1) {
            System.out.println("status = -1");
        }
        else if (status == 0) {
            System.out.println("status = NORMAL");
        }
        else if ((status & 0x00000080) != 0) {
            System.out.println("status = PRINTER_STATUS_OFFLINE");
        }
        else if ((status & 0x00400000) != 0) {
            System.out.println("status = PRINTER_STATUS_DOOR_OPEN");
        }
        else if ((status & 0x00000010) != 0) {
            System.out.println("status = PRINTER_STATUS_PAPER_OUT");
        }
        else if ((status & 0x00000800) != 0) {
            System.out.println("status = PRINTER_STATUS_OUTPUT_BIN_FULL");
        }
        else if ((status & 0x00000040) != 0) {
            System.out.println("status = PRINTER_STATUS_PAPER_PROBLEM");
        }
   }
}

I used Eclipse to run the code, i put the dll library in the folder project and the error is

PRINTER NAME = MY PRINTER
Exception in thread "main" java.lang.UnsatisfiedLinkError: com.printer.test.JniPrinterStatus.GetStatus(Ljava/lang/String;)I
    at com.printer.test.JniPrinterStatus.GetStatus(Native Method)
    at com.printer.test.TestSample.main(TestSample.java:10)

If i move the source from the package "com.printer.test" to default package the code works and show:

PRINTER NAME = MY PRINTER
status = -1

I don't know how it's possible. If i compile and run the code from command prompt without package it works.

Where is the problem?

Thank you

Sorry, actually I wanted to write a comment, but as I'm still low on reputation, I have to try and guess an answer.

• There should be no need to recompile the dll - it's just some native code to be invoked.
• The java package of the class loading the dll should not make a difference, either.

You have to take care about your system architecture: A 64-bit dll file will fail in a 32-bit JRE and vice versa. Make sure, your JRE architecture matches the dll architecture.

Another thing to take into account is your working directory. Eclipse may use a working directory different from what you used when you ran you program from console.

Last but not least, please have a look at your java.library.path variable.

This page might also help: https://www.chilkatsoft.com/java-loadLibrary-Windows.asp I covers all the details.