Articles

• Thread pools in JVM
  • CPU bound, Blocking and Non-blocking
  • CPU bound should have threads at max equal to no of CPU
    • Blocking IO operations should never be allowed on the CPU bound pool
      • They need to go to separate pool
  • Async IO polls (non blocking) should be handled by very small number of fixed, pre-allocated threads
    • These just sit idle asking kernel continually if any new async IO notification is available then forward to rest of application
    • Never do any work on this thread pool. NEVER!
• Code convention: java comments
  • Code block (note: this is not a javadoc comment) - snippet#1
  • Single line comments - snippet#2
  • Trailing comments - snippet#3
  • End of line comments - snippet#4
  • Java doc comments
    • After /** the next line follows a one space indent to align all subsequent *
    • These should NOT be placed inside contructors/methods
    • Annotations supported in javadoc
• Mockito verify cookbook
  • verify(x)
  • verify(x, y)
  • verifyZeroInteractions(x)
  • verifyNoMoreInteractions(x)
  • inOrder.verify(x)
• Git rebase explained visually
• Deep stubs in mockito
  • Mockito.RETURNS_DEFAULTS
• Reverse/foward proxies explained
• 10x engineer myth
  • tl;dr such engineers ultimately slow company down and drags scalability.
• Genius checklist
  • tl;dr no secret sauce just a list of good habits to help memory
• On time, money and health
  • tl;dr an eye opener for those in the rat race. Shows value of time in ones short life.
• Software estimation 1
  • It’s hard and not accurate but still do it
  • Estimation gets better with time
  • Size up tasks with apt. days required for each eg: {S:1, M:3, L:5, XL:10}
  • Unertainty multiplier: {low:1.1, med:1.5, high:2.0, extreme:5.0}
• Software estimation 2

Code snippets

Snippet#1

Bank apps

• The banks own apps to manage accounts.
• For the purposes of checking statements. Basic banking.

CRED

• For tracking my credit cards and their due dates so that I don’t miss anything.
• It also gives a very nice visual of the statements for the billing cycles. The raw PDFs generated by banks are too unorganized and hard to read.

INDmoney

• Tracking all my assets and liabilities. All my investments, stocks, EPF, savings and insurances get tracked here.
• It also helps manage your goals and gives a projection of whether and when it will be attained.

Paytm Money

• This is the main app I use to invest in mutual funds and gold.

Money Mgr.

• This app is for tracking all my daily expenses and income. I make entries whenever there is a transaction.
• Helps give a bigger picture and spend habits over the weeks or months.

Kite

• This is where I tried to invest in Indian stocks.
• Not really keeping up though. Managing individual stocks needs dedication. Parking this for now.

Smallcase

• Just signed up. Seems like a pretty good app. This investment vehicle is like MFs but with more control over the individual equity.

Today I Learned a.k.a TIL

FactoryBean

An amazing way to instantiate your beans based on different situations or conditions.

Example use case: I want a specific implementation of an interface based on some launch date. I can define that in the factory.

public class MessageFactoryBean implements FactoryBean<MessageInterface> {

    private MessageInterface postcard;
    private MessageInterface letter;

    public MessageInterface getObject() {
        if (your condition here) {
            return letter;
        }
        return postcard;
    }
    // other methods omitted
}

Where MessageInterface is implemented by PostCard and FormalLetter.

Disclaimer: there is only so much you can prepare in advance. You’ll mostly learn everything on the job itself but I think there are some learnings which can take off the load. Instead of trying to play catch up while on the job.

Most of the big tech companies have in-house tooling which is a beast in itself to learn (depending on the company and how much internal tools they own). Having to learn them while also trying to learn a new programming language or technology can greatly slow you from getting up to speed.

Hello world