Actually, that's not true, according to "Essential JNI", by Rob Gordon. Pp
16-17 read:
"In order for System.loadLibrary to find your native library, the directory
in which teh Shared Object Library file resides must appear in the
LD_LIBRARY_PATH environment variable. On UNIX systems, the LD_LIBRARY_PATH
environment variable is a colon-separated list of directory names. [....]
"On Win32 systems the PATH environment variable is used to located dynamic
link libraries. The PATH value is a list of directory names separated by
semicolons. [...]
"On both platforms, the list is searched in order for a file which matches
the modified argument to System.loadLibrary."
I can't find anything in the JNI Specification which describes precisely
where it will look for native libs; both it and the
System.loadLibrary/Runtime.loadLibrary method calls are very vague about the
whole process, probably to avoid excluding any platform accidentally.
If you look in the java.lang.ClassLoader source, at the end of the file
you'll find an inner class, NativeLibrary, that provides most of the support
for finding native libs. Inside of that code, after some digging around,
you'll find that two system properties appear to be the core of what gets
searched when a loadLibrary() call is executed:
usr_paths = initializePath("java.library.path");
sys_paths = initializePath("sun.boot.library.path");
These two arrays of Strings, usr_paths and sys_paths, I believe correspond
to the user-configurable and the JVM-reserved arrays of directories,
respectively. Executing this code:
public class NativeLib
{
public static void main(String[] args)
{
System.out.println("java.library.path=" +
System.getProperty("java.library.path"));
System.out.println("sun.boot.library.path=" +
System.getProperty("sun.boot.library.path"));
}
}
on a Win32 platform yields:
E:\Test>java NativeLib
java.library.path=C:\prg\java\jdk1.2.1\bin;.;C:\WINNT40\System32;C:\WINNT40;
C:\p
rg\java\jdk1.2.1\bin;C:\WINNT40\system32;C:\WINNT40;C:\Program
Files\Mts;C:\prg\
BC5\BIN;;C:\Prg\vslick\win;C:\Prg\bin;C:\Prg\WinCVS1.0.6
sun.boot.library.path=C:\prg\java\jdk1.2.1\jre\bin
E:\Test>
where the first is my PATH environment variable, and the second is
apparently coming from within the JVM itself (C:\prg\java\jdk1.2.1 is where
my JDK is installed).
Hopefully this yields some insight; comments/flames/questions welcome.
Ted Neward
Patterns/C++/Java/CORBA/EJB/COM-DCOM spoken here
http://www.javageeks.com/~tneward
"I don't even speak for myself; my wife won't let me." --Me
-----Original Message-----
From: Chris Pratt <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Tuesday, July 27, 1999 9:28 AM
Subject: Re: related to jni
>Because most servlet engines use custom classloaders, to implement the
>automatic upgrading of servlets, you must ensure that your JNI classes are
>found on the standard CLASSPATH, and NOT by the servlet engines custom
>classloader (usually the servlets directory is out).
> (*Chris*)
>
>----- Original Message -----
>From: JESS ZACHARIAS <[EMAIL PROTECTED]>
>To: <[EMAIL PROTECTED]>
>Sent: Thursday, July 29, 1999 12:44 AM
>Subject: related to jni
>
>
>> hi!
>>
>> i'am encountering a problem while using native methods from my
servlets.
>> the servlet engine used is Apache_Jserv 1.0. the webserver is installed
on
>> linux.the shared library path is /usr/lib. when a request is made to the
>> native method the error got is unsatisfied link error. the file exists
and
>> also the permissions are set right.
>>
>> can you suggest me, what could be possibly wrong?
>>
>> thank you.
>>
>>
>___________________________________________________________________________
>> To unsubscribe, send email to [EMAIL PROTECTED] and include in the
>body
>> of the message "signoff SERVLET-INTEREST".
>>
>> Archives: http://archives.java.sun.com/archives/servlet-interest.html
>> Resources: http://java.sun.com/products/servlet/external-resources.html
>> LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
>>
>
>___________________________________________________________________________
>To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
>of the message "signoff SERVLET-INTEREST".
>
>Archives: http://archives.java.sun.com/archives/servlet-interest.html
>Resources: http://java.sun.com/products/servlet/external-resources.html
>LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
___________________________________________________________________________
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff SERVLET-INTEREST".
Archives: http://archives.java.sun.com/archives/servlet-interest.html
Resources: http://java.sun.com/products/servlet/external-resources.html
LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
