Tesseract - ERROR net.sourceforge.tess4j.Tesseract - null

Question

Created a java application that uses Tesseract in order to convert a given image or pdf to a string format, when running it on my machine as a unit test using junit it runs great but when running the full system which is a restFul API run by tomcat that receives the image and runs Tesseract it gives me the following error:

23:22:36.511 [http-nio-9999-exec-3] ERROR net.sourceforge.tess4j.Tesseract - null java.lang.NullPointerException: null at net.sourceforge.tess4j.util.PdfUtilities.convertPdf2Png(PdfUtilities.java:107) at net.sourceforge.tess4j.util.PdfUtilities.convertPdf2Tiff(PdfUtilities.java:48) at net.sourceforge.tess4j.util.ImageIOHelper.getIIOImageList(ImageIOHelper.java:343) at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:213) at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:197) at ocr.OcrUtil.getString(OcrUtil.java:54) at com.tapd.server.api.handlers.IRSHandler.uploadIRSImage(IRSHandler.java:65) at com.tapd.server.api.WebAPIService.updateParentIrsForm(WebAPIService.java:250) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(ResourceMethodInvocationHandlerFactory.java:81) at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:144) at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:161) at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$ResponseOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:160) at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:99) at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:389) at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:347) at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102) at org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:309) at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271) at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267) at org.glassfish.jersey.internal.Errors.process(Errors.java:315) at org.glassfish.jersey.internal.Errors.process(Errors.java:297) at org.glassfish.jersey.internal.Errors.process(Errors.java:267) at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317) at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:292) at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1139) at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:460) at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:386) at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:334) at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:221) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:522) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:1110) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:785) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1425) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Unknown Source) [2016-09-14 23:22:36,512] [ERROR] java.lang.NullPointerException

My guess is that the tessdata folder is not located in the right place and when packaged into a Jar and run by tomcat it is misplaced, but I couldn't figure out where it should be located and I have double checked to see that all Jars are deployed correctly.

Edit: so it appears that Tesseract can't handle the path when it is on a remote server such as AWS S3, so the question is why? and how can I allow it to use a path from S3? (yes the file is public)

Answer 1

As @Piotr R mentioned the error was ghostscriptException.getCause() is null and the reason for that is that the path configured in the file object sent to Tesseract was not a valid one, now the definition of valid for Tesseract is a bit different then yours, he consider only a local address as valid, so when setting a file located on AWS S3 even if it's public it will throw an error. The solution was saving it locally and deleting it after Tesseract is done.