The Bit I changed

@Shadow public abstract boolean init();
    @Shadow private long currentTime = getCurrentTimeMillis();
    @Shadow public static long getCurrentTimeMillis();
    @Shadow private final ServerStatusResponse statusResponse = new ServerStatusResponse();
    @Shadow public abstract void applyServerIconToResponse(ServerStatusResponse statusResponse2);
    @Shadow private String motd;
    @Shadow public abstract boolean isServerRunning();
    @Shadow private boolean serverRunning = true;
    @Shadow private long timeOfLastWarning;
    @Shadow protected abstract void tick();
    @Shadow protected abstract void finalTick(CrashReport crashReport);
    @Shadow public abstract CrashReport addServerInfoToCrashReport(CrashReport crashReport);
    @Shadow public abstract File getDataDirectory();
    @Shadow private boolean serverStopped;
    @Shadow public abstract void systemExitNow();

    @Overwrite
    public void run()
    {
        try
        {
            if (this.init())
            {
                this.currentTime = getCurrentTimeMillis();
                long i = 0L;
                this.statusResponse.setServerDescription(new TextComponentString(this.motd));
                this.statusResponse.setVersion(new ServerStatusResponse.Version("1.12.2", 340));
                this.applyServerIconToResponse(this.statusResponse);

                while (this.serverRunning)
                {
                    long k = getCurrentTimeMillis();
                    long j = k - this.currentTime;

                    if (j > 2000L && this.currentTime - this.timeOfLastWarning >= 15000L)
                    {
                        LOGGER.warn("Can't keep up! Did the system time change, or is the server overloaded? Running {}ms behind, skipping {} tick(s)", Long.valueOf(j), Long.valueOf(j / 50L));
                        j = 2000L;
                        this.timeOfLastWarning = this.currentTime;
                    }

                    if (j < 0L)
                    {
                        LOGGER.warn("Time ran backwards! Did the system time change?");
                        j = 0L;
                    }

                    i += j;
                    this.currentTime = k;

                    this.tick();
                }
            }
            else
            {
                this.finalTick((CrashReport)null);
            }
        }
        catch (Throwable throwable1)
        {
            LOGGER.error("Encountered an unexpected exception", throwable1);
            CrashReport crashreport = null;

            if (throwable1 instanceof ReportedException)
            {
                crashreport = this.addServerInfoToCrashReport(((ReportedException)throwable1).getCrashReport());
            }
            else
            {
                crashreport = this.addServerInfoToCrashReport(new CrashReport("Exception in server tick loop", throwable1));
            }

            File file1 = new File(new File(this.getDataDirectory(), "crash-reports"), "crash-" + (new SimpleDateFormat("yyyy-MM-dd_HH.mm.ss")).format(new Date()) + "-server.txt");

            if (crashreport.saveToFile(file1))
            {
                LOGGER.error("This crash report has been saved to: {}", (Object)file1.getAbsolutePath());
            }
            else
            {
                LOGGER.error("We were unable to save this crash report to disk.");
            }

            this.finalTick(crashreport);
        }
        finally
        {
            try
            {
                this.serverStopped = true;
                this.stopServer();
            }
            catch (Throwable throwable)
            {
                LOGGER.error("Exception stopping the server", throwable);
            }
            finally
            {
                this.systemExitNow();
            }
        }
    }