docs: private Runnable getRunnable(ClassLoaderLeakPreventor preventor, Thread thread) {
      if(oracleTarget == null && ibmRunnable == null) { // Not yet initialized
        oracleTarget = preventor.findField(Thread.class, "target"); // Sun/Oracle JRE
        ibmRunnable = preventor.findField(Thread.class, "runnable"); // IBM JRE       
      }
  
      return (oracleTarget != null) ? (Runnable) preventor.getFieldValue(oracleTarget, thread) : // Sun/Oracle JRE  
          (Runnable) preventor.getFieldValue(ibmRunnable, thread);   // IBM JRE
    }