CODEWITHSUNDEEP
javajava-native-interface
user237515
user237515

Reputation: 31

java.lang.UnsatisfiedLinkError: Method inside dll is not accessible

I am trying to access the function available inside the .dll file. But it give exception like "Exception in thread "main" java.lang.UnsatisfiedLinkError: *.jniGetAudioInputLevel()D". DLL file is loaded but when I try to access the methods it give an error message.

According to my knowledge:-

How this in accessibility to the function can be configured out by any other idea?

Upvotes: 3

Views: 5060

Answers (3)

vovanst
vovanst

Reputation: 101

I agree with Software Monkey, but I have one very significant addition related to the function name. The function name in native library should starts from '_Java_'. In your case it should be:

_Java_com_mycompany_stuff_doSomething

I found it by chance and spent two days to figure out why JVM cannot find the function in the DLL if it is there. In my case javah generates header file with function name without underscore sign before 'Java_'. Therefore, I had to update it manually in order to make it work.

I wonder why it was not mentioned about underscore prefix in "The Java Native Interface: Programmer's Guide and Specification", "Java Native Interface 6.0 Specification" provided with Java 6 Documentation (I worked with jdk 1.6.0_30, but the JDK version should not be the issue) and some other resources.

Upvotes: 3

L. Cornelius Dol
L. Cornelius Dol

Reputation: 64026

An UnsatisfiedLinkError is also thrown if the native counterpart to a method declared native can't be found. This can easily happen if the native code was not named with the full Java package name separated using '_'.

For example,

package com.mycompany.stuff;

public native void doSomething();

Requires that a native library (DLL, so, *SRVPGM, etc depending on your system) be found and loaded with System.loadLibrary(), which contains and exports a function named

com_mycompany_stuff_doSomething

If you are certain that the native library is being loaded, my guess is that the function is not correctly named, or is not exported.

Upvotes: 6

Upul Bandara
Upul Bandara

Reputation: 5958

Normally we are getting this exception when JVM can't find the .dll file.

Upvotes: 0

Related Questions