For those who didn't install java with default settings, a systematic way for solving JNI class path problem is:
1> include "System.out.println(System.getProperty("java.library.path")); " in your "static" block, right before loading the class.
2> run your program and not surprisingly you got the err again, but this time with java.library.path info for your system. (it's important since this path name varies among systems).
3> cp your libxxx.so into the java.library.path
如果你上面看不懂的话就继续向下面看：
1、 在你载入jni类之前 放入“System.out.println( System.getProperty("java.library.path"));
2、运行你的程序你将获得java.library.path指向的目录
3、拷贝你的libxxx.so到java.library.path指向的某个目录下面。
注意：
一定要将linux下的共享库(我暂且这么叫:)命名成libxxx.so的形式，"xxx"是你在System.loadLibrary("xxx")中用到的加载库名称。
查了其他的资料：
也可以通过设置LINUX下的系统变量LD_LIBRARY_PATH来添加java.library.path，只要在启动~/.bashrc中添加如下代码然后重新登录shell，就可以将动态库放在当前目录下运行你的jni程序了。
export LD_LIBRARY_PATH=.:..:$LD_LIBRARY_PATH
另外也可以通过如下方法处理该问题
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I'm new to JNI. I see there are several ways to set JVM to look for libraries dll, so, etc.
System.setProperty("java.library.path", ".");
System.loadLibrary("hello");
That's when UnsatisfiedLinkError
java.lang.UnsatisfiedLinkError: no hello in java.library.path
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1682)
at java.lang.Runtime.loadLibrary0(Runtime.java:822)
at java.lang.System.loadLibrary(System.java:992)
at HelloWorld.main(HelloWorld.java:17)
But if I comment the line that sets the java.library.path and call the program with the command java -Djava.library.path=. HelloWorld works.
The question is: Why is not working? How should it be the property setup? I rather don't set Variables, or use -D option.