docs: public void deleteDiskCacheFiles() {
          final String methodName = "deleteDiskCacheFiles()";
          final File f = new File(swapDirPath);
          final CacheOnDisk cod = this;
          traceDebug(methodName, "cacheName=" + this.cacheName);
          AccessController.doPrivileged(new PrivilegedAction() {
              public Object run() {
                  // delete files
                  File fl[] = f.listFiles();
                  for (int i = 0; i < fl.length; i++) {
                      try {
                          fl[i].delete();
                      } catch (Throwable t) {
                          com.ibm.ws.ffdc.FFDCFilter.processException(t, "com.ibm.ws.cache.CacheOnDisk.deleteDiskCacheFiles", "908", cod);
                          traceDebug(methodName, "cacheName=" + cod.cacheName + "\nException: " + ExceptionUtility.getStackTrace(t));
                      }
                  }
                  return null;
              }
          });
      }