Importing DLL file in java application

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Hello All,

Thanks in advance.

I have CP52OO.dll file which is used to communicate with CP5200 controller. DLL is 32 bit and 64 bit dll vrsion is not available. Provider is unable to provide same.

So I imported same dll in c# project ON 64 bit system and completed my controller testing work. Testing utility is working fine.

Now the problem is I need to communicate with controller using java application only. I tried to generate c# dll and tried to import it in java application but I failed to import that dll too.

Now I finally come to conclusion that I have to develop windows service in .net using c# code, and java application will call that service.

I am started working on windows service. Meanwhile I want some better approach from world developers how can I handle this problem.

Please consider below points while providing approach :
1] As 64 bit dll is not available I can not make my java application system dependent.
2] C# code is working perfectly fine. but C# dll importing in java application also facing issue as we can not consider c# as module.
3] Approach should be robust there should not be any dependency on system, execution time should not be long.

What I have tried:

I have tried all possible ways to load library file in java. But dependency can not be removed as dll is 32 bit.

Posted 25-Sep-16 20:42pm

Tejas Sawant 13

Updated 25-Sep-16 22:00pm

Richard MacCutchan

v3

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Garth J Lancaster 26-Sep-16 3:17am

ok, some of your requirements are a bit 'hazy' ..

a) are you saying you're running a 64bit JVM and thats why you cant (JNA or JNI) call a 32bit DLL ?
b) what is CP5200.dll/CP5200 Controller ? how much data is transferred in either direction for example, how many functions does the CP5200.dll export ?
c) not sure why you're talking about c# dll import into java - why do you need c# ? you seem to have

java program -> (something) -> CP5200.dll (CP5200 Controller)

and it's the 'something' you're looking for - yet adding too much into 'something' may break your point 3 'robustness' clause / dependencies

[no name] 26-Sep-16 3:30am

Hello Gath J Lancaster,

Thanks for comment.

Please check below information about your queries

a] Yes I am using 64 bit JVM and I am not able to import 32 bit dll. I know that if I will use 32 bit jvm I may able to import dll file but I do not want to add any dependency in application like 32 bit jvm only.

b] CP5200 Controller used in LED Display hardware. CP5200.dll export multiple functions to connect, disconnect, send text, send picture like wise.

c] As I found that I am unable to import CP5200.dll in java. Then I tried to import in C#, and I am able to do that. I called multiple functions successfully using C# code. So I created new C# dll which is calling functions from CP5200.dll. Then I tried to Import C# dll in java project but I am unable to do that. So I thought that I may create one windows service using currently successfully running C# code. Java application will communicate with that windows service

Yes I am looking for something like
Java Application -> C# Windows Service -> CP5200.dll

I am not confident and sure about above approach. So asking for opinions and better approach.

Garth J Lancaster 26-Sep-16 3:40am

ok, so, why 'C# Windows Service' .. thats another dependency isnt it

why not

Java Application --- Some form of IPC ---> C++ 'server'/'service -> CP5200.dll

?

[no name] 26-Sep-16 5:12am

I am not really sure about C# service that's why I am here. I need good approach.

Could you please explain Some form of IPC means ?

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Richard MacCutchan · Answer 1 · 2016-09-25T22:00:00

Solution 1

As I have already explained in your previous two questions on this subject, you need to use the Java Native Interface to use a dynamic link library from Java.

Posted 25-Sep-16 22:00pm

Richard MacCutchan

Comments

[no name] 26-Sep-16 5:02am

I appreciate your efforts giving same answer again and again. But I am unable to use your approach that I already mentioned.

Richard MacCutchan 26-Sep-16 6:11am

Then kindly explain exactly what your problem is. Using a DLL from Java via the JNI is perfectly straightforward and does not need any C# interface or Windows service in order to make it work.

[no name] 26-Sep-16 6:15am

I am able to load dll file on 32 bit machine, but I do not want any dependency like this my application will work on 32 bit JVM only. As 32 bit dll is available from provider. 64 bit dll is not available. So I am unable to run application 64 bit JVM

Richard MacCutchan 26-Sep-16 6:21am

Then run it in the 32 bit; the dependency is causeed by the DLL and if the supplier will only provide 32 bit then you have no choice. I am also somewhat confused why you want to do this in Java if it already works in C#. you seem to be determined to make life more difficult for yourself than it needs to be.

[no name] 26-Sep-16 7:15am

As you have read above question, this dll is used to communicate with LED hardware, I have 10 different other hardware, that code is already written in core [JAVA Based] application which is communicating with all hardware.

Now you suggest me how should I communicate with LED hardware from core application.

Richard MacCutchan 26-Sep-16 7:46am

I have already made suggestions based on the information you have provided. You have a 32-bit DLL that is required in order to access some hardware device, and you wish to use it from Java. The answer is the same as I have given you in every question on this matter, and it is up to you to follow my suggestion. Repeatedly posting the same question will not alter the facts.

[no name] 27-Sep-16 7:18am

ok I used JNA and 32 bit jvm on 64 bit system. I am able to import dll file able to call all functions. I am using eclipse tool. Code is perfectly running in eclipse tool. I exported runnable jar file and try to run jar file but jar file is unable to load dll file.

I have set system variable java home path also to 32 bit jdk and jre. Same jar I tried to run on 32 bit machine it is running smoothly.

Any suggestions on same

Richard MacCutchan 27-Sep-16 9:01am

but jar file is unable to load dll file.
Sorry, but I cannot guess why that should happen. You need to do some debugging.