Inside Java and Game

Five or Six years back, people are noticing there are quite a few of Fintech companies started to offer no/very low commission stock/ETF trading.

I am not talk about the business model to make money on the pricing (difference between market maker price and the real price you get from App). I believe Robinhood and similar company had trouble with that model (lawsuits, SEC fines and so on).

I do not think I can cover all the tricks they are using. but I would like to show at least one. Here is a computing model that many firms use to cut cost and provide end user good experience, such as best market maker price.

Let me show the workflow first:

1. Usually, Fintech companies execute your order in a timed window, such as 10AM EST, 1PM EST and 3PM EST. They call it “Trading Window”. Lets say, there are 100 users want 1 share of AMZN each. you may not get best price for purchasing just 1 share. so lets group it together.
2. Once all the grouped market order is ready to execute, then send it to Market Maker as one big buy/sell order. FYI, it also cut cost to use FIX trading protocol.
3. Once the order fulfilled, it is time to split the big chunk into small pie and assign to each end user.
4. Repeat the process again on different trading Window.

Suppose you sign up an start up fintech to use DCA approach, each paycheck invest $500 with a diversified portfolio. if you trade individually, you may get just a small fraction for each Stock/Ticker in your portfolio. But this method can significantly reduce the overhead to reach out Market Maker. it can pool all the $500 cash together and figure out a trade plan, right?

As security incidents/Data breaches are happening at record pace, every company has forced to spend more effort on Information security. As an individual spent a lot of time studying cryptograph all the way back my college time.

In security field, Identity management, Data security and privacy, TVM and Security Incident Management are my main focus within those 5 years.

Identity Management

The Identity management starts with need of MFA authentication, as most of Financial regulation requires certain authentication methodology, the MFA is essential for any financial services.

First come to my world is Okta for MFA integration with company main website.

a. Migrate external customer identity management to Okta cloud smoothly without interruption of the clients.

b. Integrated Okta identity API within company home-grown authentication and authorization.

c. Partner with Okta to develop new feature and issue fixing.

d. 4 days panel discussion and training program with Okta principal architect

As cost increased with Okta, my company looked into ForgeRock as Okta replacement for cost saving. IAM and IDM are two modules that implemented and customized within company private cloud environment.

TVM

As Log4j vulnerability ruins many developers’ Christmas. Industries started to pay attention to all the open source Jar files within their application dependencies.

As many developers agree, Go programing language is cloud native focused. Here are my reading list during this holiday session for Golang

1. Learn Go with design patten in mind: https://www.smartscribs.com/tag/golang/
2. Learn Go with TDD: https://github.com/quii/learn-go-with-tests
3. Web development with go anti-pattern textbook: https://thewhitetulip.gitbook.io/bo/

As more and more system adopts Oauth as authorization protocol, here is a good read for not doing it right: https://blog.dixitaditya.com/2021/11/19/account-takeover-chain.html

Everyone is running sort of JavaScript V8 engine in your PC or Mac, but here is a RUST implementation of the desktop JavaScript engine that run fast and having small build package: https://github.com/tauri-apps/tauri

Java Switch statement new Pattern Matching feature

JEP 406 enhances the Java programming language with pattern matching for switch expressions and statements and extensions to the language of patterns. These capabilities are a preview feature in JDK 17.

Code sample:

public static String formatterPatternSwitch(Object o) {
return switch (o) {
    case Integer i -> String.format("int %d", i);
    case Long l -> String.format("long %d", l);
    case Double d -> String.format("double %f", d);
    case String s -> String.format("String %s", s);
   default -> o.toString();
  };
}

no more null pointer

static void testFooBar(String s) {
    switch (s) {
        case null         -> System.out.println("Oops");
        case "Foo", "Bar" -> System.out.println("Great");
        default           -> System.out.println("Ok");
    }
}

Oracle Java Home Page
http://www.oracle.com/technetwork/java/index.html

Java 8 Optional for Null Pointer Exception

http://www.oracle.com/technetwork/articles/java/java8-optional-2175753.html
https://community.oracle.com/docs/DOC-991686
https://community.oracle.com/docs/DOC-920950

Creating Extensible Applications/Java Service Interface
https://docs.oracle.com/javase/tutorial/ext/basics/spi.html
https://docs.oracle.com/javase/tutorial/sound/SPI-intro.html
http://docs.oracle.com/javase/6/docs/api/java/util/ServiceLoader.html

Java Selector Pattern
https://forax.github.io/2014-01-27-8650156-the_selector_pattern.html

One of the best  Java 8 tutorial  java 8 tutorial

and  his blog

Java Code Review for Security

1. SEI CERT Oracle Coding Standard for Java
2. Oracle JavaSE security Guide
3. Oracle JCA about password
   Also,  the String to store password open the hacker for memory dump.