Java Software development Technology

Spring batch, Spring Scheduler, PCF

Reading Time: < 1 minute

Was experimenting running scheduled job on PCF. One natural choice is PCF scheduler, which comes with the Pivotal Web Services (PAAS). Googled around and found this example on DZone. The spring batch code is here. There was a small typo in the manifest.yaml,

path: build/libs/payment-processing-spring-batch-0.0.1-SNAPSHOT.jar
Note the snapshot.jar file name does not match what’s specified in the build.gradle file.

The correct file name is


The rest of the manifest.yml looks good, in fact I used the following options for my spring scheduler app manifest.

no-hostname: true
no-route: true
health-check-type: none

But PCF scheduler is not available in our environment. The Spring Scheduler is used instead. I followed this Get Started Guide from Spring. In my case I need to use Cron Expression, here is the code sample and here is the guide to cron expression.

Last but not least, in my case I need to send out email notification for the cron job conditionally. I used the java email code sample here.

401k and Personal Finance

GCP Cloud Storage and PCF

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Tried two two tutorials on my personal GCP.

hello world

cloud storage (upload a file, then return a public url for download; another download link)

I may delete those bucket and files later on, as hosting costs money (app engine, cloud storage). Update: I disabled the app (here is one article talking about disable / delete app engine app). In simple term: I go to project, app engine, go to settings, click disable. Btw, I noticed all 73 cents charges for about 20 hours is from app engine.

From GCP Console Dashboard, I saw Resource

App Engine
2 versions
4 buckets

GCP Service Broker

For PCF, the approach above did not work (got an error on line 61 on the example above). I followed the steps for GCP service broker and pushed it to our pcf.

Virus Scan

Automating malware scanning for documents uploaded to Cloud Storage

PCF Sample App

It looks like with the VMWare Pivotal acquisition / integration, their hello world sample app website also moved. Here is the new link.

Software development Technology

How to generate a Lets encrypt SSL cert

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I followed the instruction here to get a free SSL cert for my website: (pretty cool, huh 🙂 (found it here)

To actually do it, I just go to the website: Scroll down a little, select the software and the system my website is running on, and it will generate all the command-lines for me, here is my link 🙂

There is one small glitch after the installation of ssl cert: that is in the wordpress, I need to set the home page from http to https

Software development Technology

Couple agile tools

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Point Poker: free (accepts donation). A nice pointing tool, click start session, for collaborators: put in name, and join the session.

Fun Retro: there are free and non-free choices. The free ones are public. It’s a bit like Trello. For that matter, if someone likes to keep it private, I think Trello is a good alternative: just put in swimming lanes such as liked, learned, lacked, longed for and action items


Career Software development Technology

Job search advice amid COVID-19 pandemic

Reading Time: 5 minutes

We are at unprecedented times, in terms of the pandemic, and the economy aftermath. The IT software dev job market is not impacted as much as some of the hard hit ones such as. travel and leisure, but nobody is also insulated when there is a typhoon. For example, locally here in St. Louis, Enterprise rent a car, the largest car rental company in the US and in the world, has laid off more than 2,000 people, IT division included. I recall about 10 years ago I wrote a post about job search, and I like to update it, amid the time change and this specific pandemic change.

Some obvious things

No onsite interviews, remote or video interview only these days. Zoom is the most popular choice, and for developers there are some white-boarding online software. Realtime white boarding is actually quite challenging, from my personal experience, on both ends. It also depends on the friendliness of the interviewer, some interviewers like to be “above the interviewee”, they give the problem, did not like to talk or give hints, and expect a quick answer right away. On the other hand, there are some other interviewers who are more open and friendly, and sometimes they will throw a dog bone to rescue. As interviewer I always try to be the former, as I personally have been in the receiving end of “bad interviewers”, and don’t like the experience. Once at an onsite interview (long time ago), a guy who maybe quite sharp, made this comment: it sounds like you did much better than the other guys came in earlier, they really don’t know what they were talking about. And at least you put up this and that, blah blah blah… is this a compliment? I guess my English is already good enough to appreciate the underlying tone there. On the other hand, I can always appreciate good / friendly interviewers, once (not in coding or white boarding) during an onsite interview, the interviewer saw my schedule and saw that I was stuck in the little room all day, he offered let’s talk a walk, and talk in the company cafeteria. It was year early / winter 2005 as I recall, in middle of New Jersey.


Below two the most popular websites now.

Indeed: note is No. 1 in terms of the number of jobs. I found my last job and current job via This is mind boggling when you think about it. I am not sure whether it exists in 2010. It’a an aggregator website. A bit like Google for information search.

LinkedIn: linkedIn became more meaningful too, I got a job offer in my last round job search and the lead is from LinkedIn. Many companies now post jobs at LinkedIn. Besides the number of jobs, we all know LinkedIn is the top 1 place that recruiters congregate. And as I built profile at LinkedIn, I also received more unsolicited messages or requests from mostly recruiters or website SEO people. Most recently I decided to be more discreet on accepting recruiters request. Most recruiters are young enthusiastic people and I bet they send out things blindly. This brings to another point.

Also, stackoverflow has a job portal, and some of the jobs are looking good too.


I think recruiters are still useful, if we are more discreet and we ask what we want. I have some recruiters friends from both ends as well: job search, or candidate technical screen. And I keep in touch with them from time to time, as a part of relationship building. Sometimes this could be a simple “hi” when the recruiter is in the hallway or in the office. I do understand, on linkedIn, or via database, sometime some younger recruiters will cold call (the reason I pick up the reason was probably the call from number is an agency I know). And we need to keep things in perspective that’s a part of their job and paycheck too. Also keep in mind we live in a small world especially in the St. Louis IT job market, and sometimes the table can turn quickly. I recall seeing a former coworker at two separate places (and I remember he was not being nice to me 🙂 I don’t have grudges against him, but I just know I probably won’t use him as reference, and vice versa.

Code Test

Not white-boarding or pairing either remote or on spot, but something like hacker rank, or Those are okay as they are usually not overly difficult, they are fair test in other words. There is some random ones, which is usually some problem a tech lead, an architect came up with. And some of those can be nasty. Once I spent 24 hours on a problem, and could not solve it. I solved it a day later. Also noted the behavior type questions on or company recruiting website. Those are easy ones to score points, so don’t waste the opportunities. Usually they let you re-do if the first recording does not look good. The coding test, if done properly, you can run the unit test on the editor and you know it’s failed or passed.

(Update 05-19-2020) There are a lot of online code playground or white boarding tools for code testing on the spot. Those are mostly collaboration tools, with some syntax highlighting. But it’s usually not as powerful as the hacker rank or as the latter ones usually have the build-tests, so basically you will know your code is good enough or not by passing those tests (tests are usually hidden though). Tools such as code labstack are still pretty useful. One thing I am not sure is how they manage the sessions. From interviewer (hiring side) point of view, it maybe helpful to give a heads up if a quick code test is expected so that the candidate is aware. I have seen candidate just bail out without even trying. I have been on the receiving end of this kind of test as well. Again the interviewers friendliness (more precisely helpfulness, do they just want to see the candidate fail, or they want to be as human as possible) varies. (sample java code question here). Also JavaScript code playground such as and .

My javascript code samples.

Last but not least, problem solving questions. One example: Suppose we have 8 balls: one is heavier than the other 7, the other 7 are identical. Now we have one balance (or scale), and we can put balls on two sides to weigh and compare. Use as few attempts as possible, to find the heavy ball? A follow up question is, if we have 2 or 3 attempts, how many balls can we handle (again one heavy ball with many identical lighter balls). 

About me. Also you may read about my other post on related topic.

Also, please note this guide on job search. I haven’t read the whole thing but it appears good. Much longer than this blog. Last but not least, this post is a good read too (Helen Anderson @helenanders26).

The Science Behind Making Software Engineering Interviews Truly Predictive of Job Performance by Geoff Roberts.

Software development

GCP Cloud SQL hibernate issue

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It complains the table does not exist when in the data.sql we were trying to insert some data. Turns out the table did exist but the default table name was lower case, while we were using Upper case both in the data.sql and the java hibernate entity. The fix is to add one line in the file. Note this is a spring boot app. Also note the data.sql was used to load initial data in spring boot.


I found out about it as I first work around the issue by doing something like shown in this article. But I was thinking this was not right. I was able to find out once I connect to the cloud sql db via proxy. Also refer to this stackoverflow discussion. 


CREATE TABLE employee (
  empName VARCHAR(100) NOT NULL

Also Spring Data

Spring data REST reference: this is by default will be shown in the root of the website.

the key seems to be adding this in pom:

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-rest</artifactId> </dependency>

Last but not least, to disable the end points or to show the available ends points for spring boot app, we can use actuator.


We can show the end points at:


401k and Personal Finance

Weekend thoughts: Zoom and Math

Reading Time: 2 minutes

For most Americans, Zoom meeting probably becomes the hottest potato in last few weeks, as we saw the pandemic situation got worse: New York, New Orleans, Detroit, Dallas, and so on. I started to using Zoom about a year ago when I started my new job, and the product experience was good. Note I have used many meeting software in the past, from Webex, Skype, GoToMeeting to google hangout, Slack, Microsoft Teams. Before Zoom GoToMeeting was my favorite. Skype probably is the worst. This is not a scientific comparison, mostly my gut feeling. Zoom is pretty standard in technology companies as well, even for interviewing (no more airplane ride, and uber ride, and hotel stay). Couple more points on Zoom. Zoom is not perfect in terms of security and privacy. And yours truly owns a few shares of Zoom. Last but not least, I do like Zoom’s founder, Eric S. Yuan (wiki English; wiki Chinese). It looks like he came to the US the same year I came. He is very much grounded person, even though is a billionaire now. I think he came from a humble background in China, which is common in China in those days (he was born in 1970, one year earlier than me).

But my point here is while Zoom is important, we should not equivalent zoom = learning or communicating or working. For that I am very much appreciative of this tweet by @DHH.

A more important task, in nowadays’ always-on culture, is the basics: reading, writing, thinking and so on. Otherwise we will end like this. Everyone makes mistakes, my point is not that Brian Williams makes stupid math mistakes. It’s more the issue two people talking about the talking points without realizing that their math is totally wrong. This is more issue in the America right now: the guy or the girl who have the microphone (in some sort of public facing position) usually don’t know what they are talking about. If in doubt, just look at the white house.

Last but not least, here is a stimulus check calculator developed by OmniCalculator.

Stimulus Check Calculator

401k and Personal Finance

Financial crisis and wall streets movies

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Hank: about Hank Paulson, available at Netflix

Too Big To Fail: on Amazon Prime

I am only curious about Wall Street and movies by Michael Lewis

401k and Personal Finance

Technology, distance learning and my meltdown

Reading Time: < 1 minuteI was thinking about this as we are at least expecting one month of distance learning for our two kids (K and 4th grade) due to the lockdown of Coronavirus pandemic. Ladue School use google suite and I think they may use google classroom for some or most teacher / students interactions. I was thinking about Zoom as Zoom recently announced free usage K-12 due to the pandemic. Many tech companies have similar initiatives. Not sure how my two kids will handle this. They are not super confident or outspoken in the class: I was hoping they could be a bit more confident (or a lot more) and be a bit more assertive.

This remind me one thing when I was already graduating from middle school. I called my classmate, at that time it’s not the direct phone, it’s like operator assisted phone. The classmate came online, and I did not know what to say (I was shy at the time too), and just freaked out in the end. I don’t think I would freak out in person. So there is my 2 cents on the distance or online learning. It may create some challenges to students who may not be comfortable with microphone or public speaking. For myself, I tried to improve myself on this aspect, I made some progress: and it was still working in progress. 🙂

401k and Personal Finance

I love Italy

Reading Time: < 1 minuteThe news coming from Italy is heartbreaking: Italy lost nearly 800 people in one day due to Coronavirus. Overall Italy lost more people than the epicenter of outbreak in China’s Hubei province (Wuhan is the capital city of Hubei, with 11 millions people). I think Italy has a population comparable to Hubei’s. In my high school years, a while ago, I watched quite a bit Italian soccer league, from Maradona to other Italian and International players. Milan has two teams: AC and Inter. And I know a little about Italy from the world history class. They are some explanations of the higher death rate in Italy. I hope things can get better from here. Besides the difference in terms of social distancing and lock down, Wuhan / Hubei did have one advantage that Italy does not have: that is China poured help from many other provinces: in total there were more than 40,000 doctors and nurses coming from all over China to help, that was about 10% of the relevant healthcare resources in China. Here is an article talking about the people in Wuhan sending off the medic teams leaving Wuhan when the mission is completed.  This kind of arrangement is difficult to accomplish in Italy, if not all possible. But note China did send some help in terms of advisors (doctors) and medical supplies to Italy, Iran, Spain and other countries (Serbia, Czech), also neighboring Asian countries too.