StackTraceHolder.javaCaptures the current thread's stack trace at construction time and stores it for later inspection. 75 lines. This is a debugging/auditing utility — used to record where an object was created so that if it causes problems later, the creation site can be identified. The constructor calls Thread.currentThread().getStackTrace() and stores the first depth elements (default 10). The toString() method formats it as a standard stack trace string.
Why not use ExceptionStackTracePrinter (#731)? That utility works on Throwable objects. This class works without an exception — it captures the stack trace at the point of object creation, before any error has occurred. It's a preemptive debugging technique: wrap a suspicious value in StackTraceHolder during construction, and if the value causes a bug later, the stack trace reveals where it came from.