tomcat 9 war file with tess4j is giving java.lang.UnsatisfiedLinkError

Question

tomcat 9 war file with tess4j is giving java.lang.UnsatisfiedLinkError

sanjeebsarkar opened this issue 3 years ago · comments

Hi ,
First of all, thank you so much for building this to help with OCR related work in Windows. Although there is a small problem when I am running this is in Windows 7 64bit, here are the VC++ redist packages I have installed :

The thing is , this program is working fine with eclipse-tomcat. In eclipse , there is Temp folder also getting created in the C:\ partition.
And the TESSDATA_PREFIX path is also set to tesseract 5.0.0 installation location's tessdata folder.

After creating a war file and pasting it in tomcat 9 / webapps folder , and then running the startup.bat file. The tomcat 9 turns on perfectly , even the tess4j folder is also getting created in the tomcat9/temp folder.

And all these are the jar files which have been included in the project build path.

So after deploying the war file when I am sending a request, I am getting this 500 error in postman,

`

<!doctype html>

<title>HTTP Status 500 – Internal Server Error</title> <style type="text/css"> h1 { font-family: Tahoma, Arial, sans-serif; color: white; background-color: #525D76; font-size: 22px; }

	h2 {
		font-family: Tahoma, Arial, sans-serif;
		color: white;
		background-color: #525D76;
		font-size: 16px;
	}

	h3 {
		font-family: Tahoma, Arial, sans-serif;
		color: white;
		background-color: #525D76;
		font-size: 14px;
	}

	body {
		font-family: Tahoma, Arial, sans-serif;
		color: black;
		background-color: white;
	}

	b {
		font-family: Tahoma, Arial, sans-serif;
		color: white;
		background-color: #525D76;
	}

	p {
		font-family: Tahoma, Arial, sans-serif;
		background: white;
		color: black;
		font-size: 12px;
	}

	a {
		color: black;
	}

	a.name {
		color: black;
	}

	.line {
		height: 1px;
		background-color: #525D76;
		border: none;
	}
</style>

HTTP Status 500 – Internal Server Error

Type Exception Report

Message Servlet execution threw an exception

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

javax.servlet.ServletException: Servlet execution threw an exception
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

Root Cause

java.lang.UnsatisfiedLinkError: The specified module could not be found.
com.sun.jna.Native.open(Native Method)
com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:288)
com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:427)
com.sun.jna.Library$Handler.&lt;init&gt;(Library.java:179)
com.sun.jna.Native.loadLibrary(Native.java:569)
com.sun.jna.Native.loadLibrary(Native.java:544)
net.sourceforge.tess4j.util.LoadLibs.getTessAPIInstance(LoadLibs.java:85)
net.sourceforge.tess4j.TessAPI.&lt;clinit&gt;(TessAPI.java:42)
net.sourceforge.tess4j.Tesseract.init(Tesseract.java:427)
net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:311)
net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:294)
net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:275)
net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:259)
com.ReadQR.readTextfromImage(ReadQR.java:184)
com.ReadQR.readTextAndSetPagesFromImage(ReadQR.java:213)
com.ReadQR.ReadQr(ReadQR.java:106)
com.Post.doPost(Post.java:58)
javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

Note The full stack trace of the root cause is available in the server logs.

Apache Tomcat/9.0.27

`

Can you please tell me what mistake I am doing ? This is running completely fine in tomcat 9 , in windows 10 64bit.

Thank you.

Quan Nguyen · Answer 1 · Fri Nov 12 2021 13:33:46 GMT+0800 (China Standard Time)

Make sure that the app have write/read access to Tomcat's temp folder. You may want to set the system property jna.debug_load=true to print the library search paths that JNA is searching for the native libraries to load.

https://github.com/java-native-access/jna/blob/master/www/FrequentlyAskedQuestions.md

sanjeeb · Answer 2 · Fri Nov 12 2021 13:39:09 GMT+0800 (China Standard Time)

Make sure that the app have write/read access to Tomcat's temp folder. You may want to set the system property jna.debug_load=true to print the library search paths that JNA is searching for the native libraries to load.

https://github.com/java-native-access/jna/blob/master/www/FrequentlyAskedQuestions.md

Hi ,
I will check the jna.debug_load , on the other hand , tomcat is able to create a folder inside its /temp folder. So read write is not an issue.

One thing, the TESSDATA_PREFIX is added to system path, do I need to add the tess4j's dlls also to system path ?

Quan Nguyen · Answer 3 · Sat Nov 13 2021 06:49:25 GMT+0800 (China Standard Time)

The environment variable TESSDATA_PREFIX should not be added to system path; it should be set to the parent directory of your tessdata directory.

Just wanted to confirm, are you running JDK 64 bit?

sanjeeb · Answer 4 · Sat Nov 13 2021 10:21:23 GMT+0800 (China Standard Time)

Hi ,
I may have said it wrong, I have added TESSDATA_PREFIX to the environment variable, and it points to the installation/tessdata folder , this is the screenshot of the tessdata path set Windows 7.

And , yes I am using jdk 64 biy, here is a cmd version output details of the java :

is there any additional setting I have to do for tomcat to help it find the dll's ?

Quan Nguyen · Answer 5 · Sat Nov 13 2021 11:43:38 GMT+0800 (China Standard Time)

TESSDATA_PREFIX variable should be set to D:\Program Files\Tesseract-OCR.

What is printed out when you run with jna.debug_load=true?

sanjeeb · Answer 6 · Sat Nov 13 2021 11:52:20 GMT+0800 (China Standard Time)

Hi , Please give me some time, I am working on the jna argument. I will change the path also.

…

On Sat, Nov 13, 2021, 09:13 Quan Nguyen ***@***.***> wrote: TESSDATA_PREFIX variable should be set to D:\Program Files\Tesseract-OCR. What is printed out when you run with jna.debug_load=true? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#223 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AN5BR6UHVQZHR5AXIOTZG6LULXNHJANCNFSM5H3ZJZ2A> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

sanjeeb · Answer 7 · Sat Nov 13 2021 12:06:40 GMT+0800 (China Standard Time)

Hi

Here is cmd output with the -D option added in tomcat 9,

Is this what you were looking for ?

Quan Nguyen · Answer 8 · Mon Nov 15 2021 10:57:21 GMT+0800 (China Standard Time)

JNA indeed tried to look up the native libraries in Tomcat's Temp directory but, for some reasons, was unable to load the DLLs found. I notice the JNA version is very old -- not sure if that could be a problem.

All I can suggest now is to create a simple console app using tess4j. Once you can get that to work, you can then try to apply to the server app.

sanjeeb · Answer 9 · Mon Nov 15 2021 10:58:58 GMT+0800 (China Standard Time)

Hi ,
Thank you for replying ,
Which version of JNA would you recommend ?

sanjeeb · Answer 10 · Mon Nov 15 2021 11:16:15 GMT+0800 (China Standard Time)

Ok , I will try to do that, can you please tell me a little bit clear as to what to do ? Create a standalone "main method" program, and create a jar file and then call it from war file ?

Quan Nguyen · Answer 11 · Mon Nov 15 2021 11:57:20 GMT+0800 (China Standard Time)

tess4j's dependencies: https://mvnrepository.com/artifact/net.sourceforge.tess4j/tess4j/4.5.5

Just try a simple console app to ensure you get all the required dependencies for tess4j and get it to run. I'm not experienced with WAR packaging or Java application server to give advice on.

sanjeeb · Answer 12 · Mon Nov 15 2021 11:59:41 GMT+0800 (China Standard Time)

Ok, Understood..
Anyway, we can close this issue, since I am stuck on my side. I will reopen this issue once I have something to report.

Thanks for all the help.

Quan Nguyen · Answer 13 · Mon Nov 15 2021 12:06:29 GMT+0800 (China Standard Time)

Good luck. Who opened the issue can close it as well.