code: public final void validateExpiration() throws TokenExpiredException {
          Date d = new Date();
          Date expD = new Date(getExpiration());
          boolean expired = d.after(expD);
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
              Tr.debug(this, tc, "Current time = " + d + ", expiration time = " + expD);
          }
          if (expired) {
              String msg = "The token has expired: current time = \"" + d + "\", expire time = \"" + expD + "\"";
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
                  Tr.debug(this, tc, msg);
              }
              throw new TokenExpiredException(expirationInMilliseconds, msg);
          }
      }
docs: Checks if the token has expired.
  
  @throws TokenExpiredException