Java 9 で StackWalker API を使用してスタック フレームをフィルタリングするにはどうすればよいですか?

import java.lang.StackWalker.StackFrame;
import java.util.*;
import java.util.stream.*;

public class StackWalkerFilterTest {
   public static void main(String args[]) {
      final <strong>List<Class></strong> filterClasses = new ArrayList<>();
      filterClasses.add(StackWalkerFilterTest.class);

      System.out.println("--- filter Frame by Class >> get first matching frame ---");
      <strong>Optional<StackFrame></strong> frameByClass = findFrameByClass(filterClasses);
      System.out.println(frameByClass.toString());

      System.out.println("--- filter Frame by Class >> get all matching frames ---");
      <strong>List<StackFrame></strong> framesByClass = findAllFramesByClass(filterClasses);
      System.out.println(framesByClass);
   }
   private static Optional<StackFrame> findFrameByClass(List<Class> filterClasses) {
      return <strong>StackWalker.getInstance</strong>(StackWalker.Option.<strong>RETAIN_CLASS_REFERENCE</strong>)
.<strong>walk</strong>(s -> s.<strong>filter</strong>(f -> filterClasses.contains(f.getDeclaringClass())).<strong>findFirst()</strong>);
   }
   private static List<StackFrame> findAllFramesByClass(List<Class> filterClasses) {
      return StackWalker.getInstance(StackWalker.Option.<strong>RETAIN_CLASS_REFERENCE</strong>).<strong>walk</strong>(
s -> s.<strong>filter</strong>(f -> filterClasses.contains(f.getDeclaringClass())).<strong>collect</strong>(Collectors.toList()));
   }
}

<strong>--- filter Frame by Class >> get first matching frame ---
Optional[StackWalkerTest.findFrameByClass(StackWalkerTest.java:20)]
--- filter Frame by Class >> get all matching frames ---
[StackWalkerTest.findAllFramesByClass(StackWalkerTest.java:23), StackWalkerTest2.main(StackWalkerTest.java:15)]</strong>