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JNA library and native library not found error

I want to use JNA to detect foreground application on Linux (Ubuntu 14). I followed this link
Find out what application (window) is in focus in Java
but I got the following error:
Exception in thread "main" java.lang.UnsatisfiedLinkError: Unable to load library 'XLib': Native library (linux-x86-64/libXLib.so) not found in resource path ([file:/home/zzhou/workspace/home_prioritization_plus/bin/, file:/home/zzhou/Downloads/jna-4.1.0.jar, file:/home/zzhou/Downloads/jna-platform-4.1.0.jar])
at com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:271)
at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:398)
at com.sun.jna.Library$Handler.<init>(Library.java:147)
at com.sun.jna.Native.loadLibrary(Native.java:412)
at com.sun.jna.Native.loadLibrary(Native.java:391)
at FunctionalityTest$XLib.<clinit>(FunctionalityTest.java:15)
at FunctionalityTest.main(FunctionalityTest.java:23)
The code is:
import com.sun.jna.Native;
import com.sun.jna.Platform;
import com.sun.jna.Pointer;
import com.sun.jna.platform.unix.X11;
import com.sun.jna.win32.StdCallLibrary;
public class FunctionalityTest {
static class Psapi {
static { Native.register("psapi"); }
public static native int GetModuleBaseNameW(Pointer hProcess, Pointer hmodule, char[] lpBaseName, int size);
}
public interface XLib extends StdCallLibrary {
XLib INSTANCE = (XLib) Native.loadLibrary("XLib", Psapi.class); // <-- PROBLEM
int XGetInputFocus(X11.Display display, X11.Window focus_return, Pointer revert_to_return);
}
public static void main(String args[]) {
if(Platform.isLinux()) { // Possibly most of the Unix systems will work here too, e.g. FreeBSD
final X11 x11 = X11.INSTANCE;
final XLib xlib= XLib.INSTANCE;
X11.Display display = x11.XOpenDisplay(null);
X11.Window window=new X11.Window();
xlib.XGetInputFocus(display, window,Pointer.NULL);
X11.XTextProperty name=new X11.XTextProperty();
x11.XGetWMName(display, window, name);
System.out.println(name.toString());
}
}
}
To import JNA library, I downloaded jna and jna-platform from https://github.com/twall/jna and use Configure Build Path... in Eclipse to add library. I did not install anything. May that be the source of the problem?
Thanks for your help.

Afaik, even for JNA, you have to load the library in Java in order for JNA to find it. (tested for win32, not linux)
Try this just above Native.loadLibrary:
System.loadLibrary("XLib");

Instantiating object in Python same as Java using jython

In Java I was able to run my code as:
(This are just sample naming)
import com.projectname.api.APIOne;
import com.projectname.api.APITwo;
import com.projectname.api.APIThree;
import com.projectname.api.APIFour;
import com.projectname.api.MainAPI;
public class TestMain {
public static void main(String[] args) {
APIOne a = APIOne.getName();
APITwo b = APIThree.getAddress();
APIFour d = b.getEmail();
MainAPI mainapi = new MainAPI();
mainapi.setEmail(d)
}
}
It is running okay, I tried converting this to Python as:
import com.projectname.api.APIOne as APIOne;
import com.projectname.api.APITwo as APITwo;
import com.projectname.api.APIThree as APIThree;
import com.projectname.api.APIFour as APIFour;
def test():
a = APIOne.getName();
b = APIThree.getAddress();
d = b.getEmail();
mainapi = MainAPI();
mainapi.setEmail(d)
test()
But is this the right way of instantiating? It make me confuse on instantiating.
Hope you could help me.

Importing a class from a java package or python module is normally written as:
from java.lang import Math
Rather than:
import java.lang.Math as Math
But, your code is correct.

I don't understand why you are confused, but this is correct, you could check the Jython documentation about instantiating Java objects using Jython and instantiates the objects the same way as you do.

Call DLL from Java using JNA

I am new to accessing DLLs from Java using JNA. I need to access methods from a class within a DLL(written in .net). Form this sample DLL below, I am trying to get AuditID and Server ID. I am ending with the following error while I am running my code. Any guidance really appreciated.
/// Error ///
Exception in thread "main" java.lang.UnsatisfiedLinkError: Error looking up function 'GetEnrollcontext': The specified procedure could not be found.
//DLL File Code//
SampleDLL.ProfileEnroll enrollcontext = new SampleDLL.ProfileEnroll();
enrollcontext.Url =” url”;
enrollcontext.AuditIdType = SampleDLL.ProfileId;
enrollcontext.AuditId = “22222222 “;
enrollcontext.ServerId = “server1”;
/// Java Code ///
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Structure;
import dllExtract.DLLExtractTest.SampleDLL.Enrollcontext;
public class SampleDLLExtract {
public interface SampleDLL extends Library {
SampleDLL INSTANCE = (SampleDLL) Native.loadLibrary("SampleDLL",
SampleDLL.class);
public static class Enrollcontext extends Structure {
public String auditId;
public String serverId;
}
void GetEnrollcontext(Enrollcontext ec); // void ();
}
public static void main(String[] args) {
SampleDLL sdll = SampleDLL.INSTANCE;
SampleDLL.Enrollcontext enrollContext = new SampleDLL.Enrollcontext();
sdll.GetEnrollcontext(enrollContext);
System.out.println(sdll.toString(sdll.GetEnrollcontext(enrollContext)));
}
}

in fact there is a solution for you to use C#, VB.NET or F# code via JNA in Java (and nothing else)! and it is also very easy to use:
https://www.nuget.org/packages/UnmanagedExports
with this package all you need to do is, add [RGiesecke.DllExport.DllExport] to your methods like that:
C# .dll Project:
[RGiesecke.DllExport.DllExport]
public static String yourFunction(String yourParameter)
{
return "CSharp String";
}
Java Project:
public interface jna extends Library {
jna INSTANCE = (jna) Native.loadLibrary("yourCSharpProject.dll", jna.class);
public String yourFunction(String yourParameter);
}
use it in the code:
System.out.println(jna.INSTANCE.yourFunction("nothingImportant"));
Viola!
As already mentioned it works very easy, but this solution has some limitations:
only available for simple datatypes as parameter & return values
no MethodOverloading available. yourFunction(String yourParameter) and yourFunction(String yourParameter, String yourSecondParameter) does not work! you have to name them differently
Use arrays as parameter or return values. (JNA offers StringArray, but I am not able to use them in C#) (maybe there is a solution, but I couldn't come up with one so far!)
if you export a method you can't call it internally in your C# code (simple to bypass that by the following:
.
[RGiesecke.DllExport.DllExport]
public static Boolean externalAvailable(String yourParameter)
{
return yourInternalFunction(yourParameter);
}
With C# it works great, with VB.NET and F# I have no experience.
hope this helps!

Using DLL in java through JNA

I am using dll in java using JNA, but i am getting below error
Exception in thread "main" java.lang.UnsatisfiedLinkError: Error looking up function 'GetStatus': The specified procedure could not be found.
Not getting how to resolve this issue?
Please help.
Here is java code
import com.sun.jna.Library;
import com.sun.jna.Native;
/** Simple example of native library declaration and usage. */
public class First {
public interface TEST extends Library {
public String GetStatus();
}
public static void main(String[] args) {
TEST obj = (TEST ) Native.loadLibrary("TEST ", TEST .class);
System.out.println( obj.GetStatus());
}
}

This Nugget is super easy to use and works perfectly. https://www.nuget.org/packages/UnmanagedExports
You need Visual Studio 2012 (express).
Once installed, just add [RGiesecke.DllExport.DllExport] before any static function you want to export. That's it!
Example:
C#
[RGiesecke.DllExport.DllExport]
public static int YourFunction(string data)
{
/*Your code here*/
return 1;
}
Java
Add the import at the top:
import com.sun.jna.Native;
Add the interface in your class. Its your C# function name preceded by the letter "I":
public interface IYourFunction extends com.sun.jna.Library
{
public int YourFunction(String tStr);
};
Call your DLL where you need it in your class:
IYourFunction iYourFunction = (IYourFunction )Native.loadLibrary("full or relative path to DLL withouth the .dll extention", IYourFunction.class);//call JNA
System.out.println("Returned: " + IYourFunction.YourFunction("some parameter"));
EDIT:
If the DLL is 32bit, the JDK/JRE has to be 32bit as well. Add the following check to your code:
if(!System.getProperty("os.arch").equals("x86")) {
throw new Exception(".NET DLL " + "32bits JRE/JDK is required. Currently using " + System.getProperty("os.arch") + ".\r\nTry changing your PATH environement variable.");
}

Java binary compatibility issue: sun.font.FontManager class became interface

I am using the Lobo - Java Web Browser library, and it gives me an exception which after some research I determined could be due to the library having been complied against an older version of Java.
The code is as follows:
import java.io.IOException;
import org.lobobrowser.html.UserAgentContext;
import org.lobobrowser.html.parser.DocumentBuilderImpl;
import org.lobobrowser.html.parser.InputSourceImpl;
import org.lobobrowser.html.test.SimpleUserAgentContext;
import org.xml.sax.SAXException;
public class Cobratest
{
public static void main(String[] args) throws SAXException, IOException
{
UserAgentContext uAgent = new SimpleUserAgentContext();
DocumentBuilderImpl docBuild = new DocumentBuilderImpl(uAgent);
docBuild.parse(new InputSourceImpl("http://dic.amdz.com/"));
}
}
and the stack trace is:
Exception in thread "main" java.lang.IncompatibleClassChangeError: Found interface sun.font.FontManager, but class was expected
at org.lobobrowser.util.gui.FontFactory.createFont(FontFactory.java:210)
at org.lobobrowser.util.gui.FontFactory.createFont_Impl(FontFactory.java:180)
at org.lobobrowser.util.gui.FontFactory.createFont(FontFactory.java:127)
at org.lobobrowser.util.gui.FontFactory.getFont(FontFactory.java:98)
at org.lobobrowser.html.style.StyleSheetRenderState.<clinit>(StyleSheetRenderState.java:43)
at org.lobobrowser.html.domimpl.NodeImpl.<clinit>(NodeImpl.java:39)
at org.lobobrowser.html.parser.DocumentBuilderImpl.createDocument(DocumentBuilderImpl.java:143)
at org.lobobrowser.html.parser.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:97)
when I examined org.lobobrowser.util.gui.FontFactory.createFont I found out there is an interface called FontManager which changed from the previous version of Java. In this FontFactory class, they used a class of this interface which is no longer available. How can I fix this problem?
the interface FontManager:
package sun.font;
import java.awt.Font;
import java.awt.FontFormatException;
import java.io.File;
public interface FontManager {
public static final int NO_FALLBACK = 0;
public static final int PHYSICAL_FALLBACK = 1;
public static final int LOGICAL_FALLBACK = 2;
public boolean registerFont(Font font);
public void deRegisterBadFont(Font2D font2d);
public Font2D findFont2D(String string, int i, int i1);
public Font2D createFont2D(File file, int i, boolean bln, CreatedFontTracker cft) throws FontFormatException;
public boolean usingPerAppContextComposites();
public Font2DHandle getNewComposite(String string, int i, Font2DHandle fdh);
public void preferLocaleFonts();
public void preferProportionalFonts();
}
and the class used in the library which is not available:
return FontManager.getCompositeFontUIResource(new Font(name, style, size));

I think 'sun.font.FontManager'was removed with Java7, so if you must use it (I'd recommend against it and look for another package instead) you could try running it with java6.

The LoboBrowser project has been superseded by LoboEvolution, but there's a patch that's mentioned for the obsolete LoboBrowser implementation.
Update FontFactory.java to import a public method and revise the createFont method as follows:
import static javax.swing.text.StyleContext.*;
private Font createFont(String name, int style, int size) {
return getDefaultStyleContext().getFont(name, style, size);
}

javax.swing.text.StyleContext.getDefaultStyleContext.getFont might work for you, across JDK releases.
See further http://elliotth.blogspot.com.au/2007/04/far-east-asian-fonts-with-java-7-on.html