Develop Reference

JNI call to dll method does not work - UnsatisfiedLinkError

I have created Java proxies with swig from a Header File.
Now i get an UnsatisfiedLinkError which (i think) points to a non existing method.
LcDll:DLL_PROCESS_ATTACH
Exception in thread "main" java.lang.UnsatisfiedLinkError: barJNI._LC_application_get()J
at barJNI._LC_application_get(Native Method)
at bar.LC_application_get(bar.java:31)
at LumicamTest.main(LumicamTest.java:171)
LcDll:DLL_THREAD_DETACH
LcDll:DLL_THREAD_DETACH
LcDll:DLL_THREAD_DETACH
LcDll:DLL_THREAD_DETACH
LcDll:DLL_THREAD_DETACH
LcDll:DLL_THREAD_DETACH
LcDll:DLL_PROCESS_DETACH
The LcDll messages show me, that the DLL could get loaded.
I want to call the following method:
public final static native long _LC_application_get();
The methow was generated by swig as LC_application_get(); without underscore.
I have tried both variants, with and without underscore, cause the DLL explorer shows the method with underscore.
The dll explorer shows the method as following: _LC_application_get#0
I suppose that the #0 means, that the method has no parameters in it's signature.
Has someone an idea, what could be the problem?
thanks in advance

Compiling my project with AOT throws a NullPointerException

I'm trying to build an uberjar using lein uberjar. During compiling, the following gets thrown:
Exception in thread "main" java.lang.NullPointerException, compiling:(/tmp/form-init8223412427040046857.clj:1:73)
at clojure.lang.Compiler.load(Compiler.java:7391)
at clojure.lang.Compiler.loadFile(Compiler.java:7317)
at clojure.main$load_script.invokeStatic(main.clj:275)
at clojure.main$init_opt.invokeStatic(main.clj:277)
at clojure.main$init_opt.invoke(main.clj:277)
at clojure.main$initialize.invokeStatic(main.clj:308)
at clojure.main$null_opt.invokeStatic(main.clj:342)
at clojure.main$null_opt.invoke(main.clj:339)
at clojure.main$main.invokeStatic(main.clj:421)
at clojure.main$main.doInvoke(main.clj:384)
at clojure.lang.RestFn.invoke(RestFn.java:421)
at clojure.lang.Var.invoke(Var.java:383)
at clojure.lang.AFn.applyToHelper(AFn.java:156)
at clojure.lang.Var.applyTo(Var.java:700)
at clojure.main.main(main.java:37)
Caused by: java.lang.NullPointerException
at clojure.string$lower_case.invokeStatic(string.clj:217)
at clojure.string$lower_case.invoke(string.clj:213)
at kappa.joke_classifier$is_jokable_QMARK_.invokeStatic(joke_classifier.clj:32)
at kappa.joke_classifier$is_jokable_QMARK_.invoke(joke_classifier.clj:29)
at kappa.core$maybe_joke.invokeStatic(core.clj:47)
at kappa.core$maybe_joke.invoke(core.clj:45)
at clojure.core$run_BANG_$fn__7276.invoke(core.clj:7393)
at clojure.lang.PersistentVector.reduce(PersistentVector.java:341)
at clojure.core$reduce.invokeStatic(core.clj:6544)
at clojure.core$run_BANG_.invokeStatic(core.clj:7388)
at clojure.core$run_BANG_.invoke(core.clj:7388)
at kappa.core$run.invokeStatic(core.clj:58)
at kappa.core$run.invoke(core.clj:53)
at kappa.core$_main.invokeStatic(core.clj:66)
at kappa.core$_main.doInvoke(core.clj:61)
at clojure.lang.RestFn.invoke(RestFn.java:397)
at clojure.lang.Var.invoke(Var.java:375)
at user$eval5.invokeStatic(form-init8223412427040046857.clj:1)
at user$eval5.invoke(form-init8223412427040046857.clj:1)
at clojure.lang.Compiler.eval(Compiler.java:6927)
at clojure.lang.Compiler.eval(Compiler.java:6917)
at clojure.lang.Compiler.load(Compiler.java:7379)
... 14 more
The code using string/lower-case looks as follows:
(defn is-jokable? [msg]
(and
(> 30 (count msg))
(= :positive (.classify classifier (str/lower-case msg)))
(< 1 (:positive (.probabilities classifier (str/lower-case msg))))))
As can be seen from the stack trace, my -main function calls a function that eventually calls is-jokable, and str/lower-case seems to be called with nil. If I understand correctly this is because of the AOT compilation happening for uberjars, but I'm not quite sure why exactly this problem occurs... I've already tried to read up on AOT, but didn't find anything helpful. Can you explain the inner workings of AOT to me?

I'm almost embarrassed I have posted this, it must have been too late in the night... ;)
I got completely distracted by the compiling and invokeStatic hints in the stacktrace, and just now found that this was indeed an everyday bug where I expected a map to contain a key/value pair that wasn't existent, leading to nil being passed to the function in question.
Thanks for the helpful comments!

Exception in thread "main" java.lang.RuntimeException: Not yet implemented

I am fetching some problem when I trying to print Arabic letter by using DirectPrint bean. This is a pjc. English fonts are printed fine, but when I want to print Arabic there is showing a exception below:
Exception in thread "main" java.lang.RuntimeException: Not yet implemented
at org.pdfbox.pdmodel.font.PDType0Font.drawString(PDType0Font.java:75)
at org.pdfbox.pdfviewer.PageDrawer.showCharacter(PageDrawer.java:160)
at org.pdfbox.util.PDFStreamEngine.showString(PDFStreamEngine.java:409)
at org.pdfbox.util.operator.ShowTextGlyph.process(ShowTextGlyph.java:80)
at org.pdfbox.util.PDFStreamEngine.processOperator(PDFStreamEngine.java:452)
at org.pdfbox.util.PDFStreamEngine.processSubStream(PDFStreamEngine.java:215)
at org.pdfbox.util.PDFStreamEngine.processStream(PDFStreamEngine.java:174)
at org.pdfbox.pdfviewer.PageDrawer.drawPage(PageDrawer.java:104)
at org.pdfbox.pdmodel.PDPage.print(PDPage.java:741)
at sun.print.RasterPrinterJob.printPage(RasterPrinterJob.java:1936)
at sun.print.RasterPrinterJob.print(RasterPrinterJob.java:1431)
at sun.print.RasterPrinterJob.print(RasterPrinterJob.java:1247)
at dsd.printing.DirectPrint.main(DirectPrint.java:842)
Please help to solve this issue.

Seems like the Arabic characters are not implemented to be converted by the pdfbox library you're using.

What version of PDFBox you are using? What I see from here:
Exception in thread "main" java.lang.RuntimeException: Not yet implemented
at org.pdfbox.pdmodel.font.PDType0Font.drawString(PDType0Font.java:75)
That it says PDType0Font class and drawString method straightly throws 'Not yet implemented' exception but i.e. if I check one of the latest version (i.e. 1.8.10) I can see the method implemented: here
If I would be I would try to change the version of pdfbox library and try again.
EDIT: Thanks to Tilman, latest version info from his comment: 2.0 has been released friday, it should be available for maven: mvnrepository.com/artifact/org.apache.pdfbox/pdfbox

No Such method error during transformation to pdf in Java

I have a problem while transforming the xslt to pdf in java, i am following the same process posted in this link
"Java Transformation to PDF".
Error:
`
Caused by: java.lang.NoSuchMethodError: org.apache.xmlgraphics.java2d.GraphicContext.<init>(Lorg/apache/xmlgraphics/java2d/GraphicContext;)V
at org.apache.fop.render.intermediate.IFGraphicContext.<init>(IFGraphicContext.java:50)
at org.apache.fop.render.intermediate.IFGraphicContext.clone(IFGraphicContext.java:56)
at org.apache.fop.render.intermediate.IFRenderer.saveGraphicsState(IFRenderer.java:632)
at org.apache.fop.render.intermediate.IFRenderer.startViewport(IFRenderer.java:885)
at org.apache.fop.render.intermediate.IFRenderer.startVParea(IFRenderer.java:878)
at org.apache.fop.render.AbstractRenderer.renderRegionViewport(AbstractRenderer.java:289)
at org.apache.fop.render.intermediate.IFRenderer.renderRegionViewport(IFRenderer.java:731)
at org.apache.fop.render.AbstractRenderer.renderPageAreas(AbstractRenderer.java:249)
at org.apache.fop.render.AbstractRenderer.renderPage(AbstractRenderer.java:230)
at org.apache.fop.render.intermediate.IFRenderer.renderPage(IFRenderer.java:580)
at org.apache.fop.area.RenderPagesModel.addPage(RenderPagesModel.java:114)
at org.apache.fop.layoutmgr.AbstractPageSequenceLayoutManager.finishPage(AbstractPageSequenceLayoutManager.java:312)
at org.apache.fop.layoutmgr.PageSequenceLayoutManager.finishPage(PageSequenceLayoutManager.java:167)
at org.apache.fop.layoutmgr.PageSequenceLayoutManager.activateLayout(PageSequenceLayoutManager.java:109)
at org.apache.fop.area.AreaTreeHandler.endPageSequence(AreaTreeHandler.java:238)
at org.apache.fop.fo.pagination.PageSequence.endOfNode(PageSequence.java:120)
at org.apache.fop.fo.FOTreeBuilder$MainFOHandler.endElement(FOTreeBuilder.java:349)
at org.apache.fop.fo.FOTreeBuilder.endElement(FOTreeBuilder.java:177)
at net.sf.saxon.event.ContentHandlerProxy.endElement(ContentHandlerProxy.java:391)
at net.sf.saxon.event.ProxyReceiver.endElement(ProxyReceiver.java:174)
at net.sf.saxon.event.NamespaceReducer.endElement(NamespaceReducer.java:213)
at net.sf.saxon.event.ComplexContentOutputter.endElement(ComplexContentOutputter.java:417)
at net.sf.saxon.instruct.ElementCreator.processLeavingTail(ElementCreator.java:301)
at net.sf.saxon.instruct.Block.processLeavingTail(Block.java:409)
at net.sf.saxon.instruct.Instruction.process(Instruction.java:94)
at net.sf.saxon.instruct.ElementCreator.processLeavingTail(ElementCreator.java:298)
at net.sf.saxon.instruct.Template.applyLeavingTail(Template.java:175)
at net.sf.saxon.instruct.ApplyTemplates.applyTemplates(ApplyTemplates.java:343)
at net.sf.saxon.Controller.transformDocument(Controller.java:1736)
at net.sf.saxon.Controller.transform(Controller.java:1560)
at mypackage.v2.business.pdf.XMLtoPDF.convertXMLPDF(XMLtoPDF.java:103)
... 51 more
java.lang.ClassCastException: java.lang.NoSuchMethodError cannot be cast to java.lang.Exception
`
Please let me know what could be the problem.

As described in the documentation
Thrown if an application tries to call a specified method of a class (either static or instance), and that class no longer has a definition of that method.
Here's how this can happen. Imagine you built some code that used a library with a method called foo(). You compiled your project and then later decided to upgrade the library. You do this by overwriting the old jar file with the new one. You don't recompile your code.
But what you didn't know is the new library removed the foo() method. Now if you run your code, it will throw this exception because your compile code calls this method and it's no longer there.
In your specific case, this isn't necessarily your code with the problem. It could be that you have one library that uses another library and the problem is there (for example, Library X uses version 2 of Library Y, but you only have Library Y version 1 in your classpath). If this is happening, you need to make sure the libraries are using the version they expect.
For your specific problem, you need to find the version of the jar that has org.apache.xmlgraphics.java2d.GraphicContext in it and it needs to have a constructor that takes a... list of org/apache/xmlgraphics/java2d/GraphicContext... maybe. I forget what (L...;)V means.

Java game not working

I found this java source code for a brick breaker game online. I downloaded it and tried to run it but it gives me a NullPointerException. What is giving this exception and how do I fix it? Thanks.
http://zetcode.com/tutorials/javagamestutorial/breakout/
Here is the stacktrace:
Exception in thread "main" java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(ImageIcon.java:181)
at Ball.<init>(Ball.java:16)
at Board.gameInit(Board.java:48)
at Board.addNotify(Board.java:43)
at java.awt.Container.addNotify(Container.java:2578)
at javax.swing.JComponent.addNotify(JComponent.java:4685)
at java.awt.Container.addNotify(Container.java:2578)
at javax.swing.JComponent.addNotify(JComponent.java:4685)
at java.awt.Container.addNotify(Container.java:2578)
at javax.swing.JComponent.addNotify(JComponent.java:4685)
at javax.swing.JRootPane.addNotify(JRootPane.java:739)
at java.awt.Container.addNotify(Container.java:2578)
at java.awt.Window.addNotify(Window.java:663)
at java.awt.Frame.addNotify(Frame.java:470)
at java.awt.Window.show(Window.java:859)
at java.awt.Component.show(Component.java:1584)
at java.awt.Component.setVisible(Component.java:1536)
at java.awt.Window.setVisible(Window.java:842)
at Breakout.<init>(Breakout.java:14)
at Breakout.main(Breakout.java:18)
Exception in thread "Timer-0" java.lang.NullPointerException
at Board$ScheduleTask.run(Board.java:110)
at java.util.TimerThread.mainLoop(Timer.java:512)
at java.util.TimerThread.run(Timer.java:462)
Apparently this code is supposed to work, but it isn't.

You probably didn't download the images as well, or at least didn't put them in the right folder. Make sure you put the images here:
Browse to Ball.java, go two folder levels up, create there a folder called images and put there your images.