This patch refactors the native library loading implementation out of ClassLoader and move them to jdk.internal.loader package. This introduces a new NativeLibraries abstraction which loads and registers the loaded native libraries. Previously it was maintained in a nativeLibrary map in each ClassLoader instance and one systemNativeLibraries for the null loader case. With this change, each ClassLoader and BootLoader have its own NativeLibraries instead. NativeLibraries.java and NativeLibraries.c are mostly refactored from the existing code. Only minor cleanups are applied. This refactoring enables Panama LookupLibrary to further experiment and allow loading of a native library without the restriction that a native library can only be loaded by one class loader. The restriction is important for System::loadLibrary in loading JNI libraries that implements JNI native methods and so remain unchanged. This patch follows up the change introduced by JDK-8227587 which adds BootLoader::loadLibrary. It should belong a helper classes instead of BootLoader and this helper method is to avoid doPrivileged call if no security manager is installed for startup performance improvement. Several `privilegedXXX` methods were added for the same purpose for example sun.security.action.GetPropertyAction::privilegedGetProperty and privilegedGetProperties. So I think sun.security.action.LoadLibraryAction is a proper place. Webrev: http://cr.openjdk.java.net/~mchung/jdk15/webrevs/8228336/webrev.00/ Thanks Mandy