How to influence search path of System.loadLibrary() through Java code?

Question

In a Java project, I am using a third-party library that loads some native library via

System.loadLibrary(\"libName\");

I\'d like to be able to

Answer 1

Just recently ran into this issue and using OpenJDK where a NullPointerException is thrown (as 0-0 mentioned the Samil's answer). The following works in OpenJDK and should work with Oracle JDK as well.

(Option 1) Replace the java.library.path

System.setProperty("java.library.path", newPath);
Field field = ClassLoader.class.getDeclaredField("sys_paths");
field.setAccessible(true);
field.set(ClassLoader.getSystemClassLoader(), new String[]{newPath});

(Option 2) Add to existing java.library.path

String libPath = System.getProperty("java.library.path");
String newPath;

if (libPath == null || libPath.isEmpty()) {
    newPath = path;
} else {
    newPath = path + File.pathSeparator + libPath;
}

System.setProperty("java.library.path", newPath);

Field field = ClassLoader.class.getDeclaredField("sys_paths");
field.setAccessible(true);

// Create override for sys_paths
ClassLoader classLoader = ClassLoader.getSystemClassLoader(); 
List newSysPaths = new ArrayList<>();
newSysPaths.add(path);  
newSysPaths.addAll(Arrays.asList((String[])field.get(classLoader)));

field.set(classLoader, newSysPaths.toArray(new String[newSysPaths.size()]));