How to check if an java native method is implemented?

Question

我想在使用本机方法之前检查它的实现，但我不知道如何。

Answer 1

If a native method of a class isn't defined for your platform, the classloader will throw an java.lang.UnsatisfiedLinkError . So your test could be

try {
  Class.forName("your.class.with.NativeCode");
} catch (UnsatisfiedLinkError e) {
  // the implementation for the methods cannot be linked.

}

This code would need to be in an unrelated class that doesn't have any direct dependency to the class with native code. Otherwise this class cannot be loaded as well.