The method `java.lang.Thread.countStackFrames()` has been removed in this release. This method dates from JDK 1.0 as an API for counting the stack frames of a suspended thread. The method was deprecated in JDK 1.2 (1998), deprecated for removal in Java 9, and re-specified/degraded in Java 14 to throw `UnsupportedOperationException` unconditionally.

`java.lang.StackWalker` was added in Java 9 as a modern API for walking the current thread's stack.