BC TECH

Saved by @jacobhtml

Tagir Valeev
@tagir_valeev 3 years, 2 months ago 444 views

Save to PDF Share See On Twitter

Ever wondered how the JVM debugger 'Evaluate' feature works in IDEs? Long ago I thought that the Java debug interface (JDI) actually allows you to specify the expression and get back its value.

However, this is not quite possible: there's no Java language compiler inside the JVM. When the process is paused JDI allows you to read or write any variables and fields or even execute an existing method with given arguments. But nothing like addition or multiplication.

On the other hand, #IntelliJIDEA debugger allows you to evaluate even statements! You can write there `for`, `if`, `while`, `switch` - whatever. You can even declare local variables. So how this works?

The answer is simple: IDEA debugger has a built-in interpreter for Java! If you access an existing variable or a field, call a method or instantiate an object, it queries JDI. Otherwise, IDE itself does all the calculations.

The amusing thing is that debugger authors didn't bother to make it as strict as Java itself, so the language inside the interpreter is a much more permissive version of Java. For example, you don't need to initialize variables there! Default values like 0 are used automatically.

Of course, final variables could be changed. Why artificial limitations?

Another thing: most of the casts are not necessary. This interpreted Java more resembles dynamically typed languages like JavaScript. Duck-typing works: if there's a method, we can call it. Even if the highlighter complains.

Switch statements and expressions are more permissive there: you can switch over any type. Also, no default is necessary for switch expressions. If it's not visited, the evaluation will be successful.

In addition to use any type, you can use any expressions as case labels, not just constants! The first matching branch will be executed.

Finally, even if your project still uses Java 6 JDK, it doesn't stop you from using new language features. For example, 'var' declarations and patterns in instanceof work perfectly, because they are interpreted by IDE, not by your JDK. Just ignore error messages!

More from Tech

Jared Spool
@jmspool

A common misunderstanding about Agile and “Big Design Up Front”:

There’s nothing in the Agile Manifesto or Principles that states you should never have any idea what you’re trying to build.

You’re allowed to think about a desired outcome from the beginning.

It’s not Big Design Up Front if you do in-depth research to understand the user’s problem.

It’s not BDUF if you spend detailed time learning who needs this thing and why they need it.

It’s not BDUF if you help every team member know what success looks like.

Agile is about reducing risk.

It’s not Agile if you increase risk by starting your sprints with complete ignorance.

It’s not Agile if you don’t research.

Don’t make the mistake of shutting down critical understanding by labeling it Bg Design Up Front.

It would be a mistake to assume this research should only be done by designers and researchers.

Product management and developers also need to be out with the team, conducting the research.

Shared Understanding is the key objective

I\u2019d recommend that the devs participate directly in the research.

If the devs go into the first sprint with a thorough understanding of the user\u2019s problems, they are far more likely to solve it well.
— Jared Spool (@jmspool) November 18, 2018

Big Design Up Front is a thing to avoid.

Defining all the functionality before coding is BDUF.

Drawing every screen and every pixel is BDUF.

Promising functionality (or delivery dates) to customers before development starts is BDUF.

These things shouldn’t happen in Agile.

Venkatesh Rao
@vgr

There are only 3 real challenges to free speech at the tech level a) the need for CDNs at scale b) distortions of net neutrality c) nation-state firewalls.

All other claims are about social governance on private sites, where applying free speech doctrine is a stretch at best

Baseline free speech has expanded modestly since 1776 or whatever your reference point is.

About 20% beyond core case of government-critical speech in formally public spaces and media I'd say.

You can (for example) have more kinds of conversations in a bar without getting punched or kicked out by other patrons or management. You can teach more things in colleges than 100 years ago.

That's a genuine de facto increase in practical, informal free speech/expression.

But online free "speech" is, as @reneed has pointed out, not an expansion of free speech at all, but an expansion of reach. It is like the secondary freedom of the press to print as many copies as they can afford, not primary freedom to say what they want

If a newspaper wants to print more copies it has buy more printing equipment and front more upfront costs. Reach for a paper publication is not "free", but a function of desired circulation, which in turn is a function of demand prediction etc. But that logic is obscured online.

Advertisement

Yoel Roth
@yoyoel

We’ve recently seen research about so-called “bots” and misinformation on Twitter and wanted to share our perspective on why findings that might seem remarkable at first are likely inaccurate. We’re working on a more detailed explanation, but some comments for now.

We continue to be excited by the research opportunities that Twitter data provides. Our service is the largest source of real-time social media data, and we make this data available to the public for free through our public API. No other major service does this.

Many researchers, academics, and journalists use our public API — a set of tools for programmatically accessing information on Twitter. We make all public Twitter content available via our APIs. You can learn more about them here:

The basic issue with much of the research based on our public APIs is simple: The APIs don't provide insight into our defensive actions to protect Twitter from manipulation, including bots.

Because of this, API-based research can't distinguish between accounts we've already identified as bad (and hidden or removed) and real, authentic ones.

$Jen \u26a1$

Jen ⚡
@leoniedelt

Been reading up a lot about these jabs, esp as I know they are going to be a condition of a return to normality

Was on a zoom call last evening with a testing company that had some fascinating evidence on protection etc.

I have more reading to do.

I do not want to be coerced into something I don't want, BUT i want normal back as soon as possible.

Basically i'm at the point in my isolation and thinking that I'll take whatever just so this bullshit can end.

That is a desperate mindset, but so is 12 months of being cut off from the world.

All i have is what goes round and round in my head.

There's no one else to help balance it.

So i'm in group 6, and my surgery are doing group 6 right now. And i am at the point i want to do it to get it DONE.

And also to study what happens. Because i have that kind of mind.

I remember Pandemrix.

But we live with risk every day.

I risk my life climbing walls with only a harness around my waist to catch me as i lean back and fall off

And rational risk assessment is at the heart of everything going wrong these last 12 months

$Thomas A. Fine \U0001f1fa\U0001f1f8$

Thomas A. Fine 🇺🇸...
@thomasafine

So is Apple's anti-theft security a wonderful boon to users?

Or is it just another evil corporation strengthening it's monopoly power?

I had the misfortune of buying a 2018 Mac Mini on ebay a few days ago. Unfortunately, it had not been wiped, and it's security defaults had never been changed.

This essentially turns it into a very shiny paperweight.

And this is where everybody jumps to blame the victim. "But everybody knows you have to make sure the seller wipes the Mac."

My how the corporate overlords have trained us to be their apologists.

To be clear, I'm a software engineer. Part of my job is supporting Mac users. Where I work, people hold on to their computers for several years generally, and the T2 chips are only a couple of years old, so I hadn't run into this situation at work.

Of course, I'd read about them, but I was confident that whatever condition the computer arrived in, I'd likely be able to deal with it.

Unfortunately I hadn't read up enough to be an expert on their T2 chip and Activation lock.

You May Also Like

$Julien \U0001f332$

Julien 🌲
@julien

1/ there is this sense when you are young that your accomplishments need to be a list of things that seem impressive to others. A list of several items you did.

This isn't actually right, so here is another suggestion.

2/ I remember being 26 and writing about reading 52 books a year. I wrote blog posts about it. They got copied. It became "a thing." Now it's in Twitter bios. It looks impressive but it's insanely useless and I shouldn't have done it.

3/ what I should have known at that time is that only young idiots like myself, with no accomplishments, find list of tiny achievements impressive. Anyone who has actually done anything of substance doesn't gaf

4/ what is actually difficult, and worthwhile, instead is to do ONE single thing for a very, very long time. It's much harder and much rarer and results in outlier outcomes much more often.

Of course you can find this out too late if you are chasing the dragon of Ted talks etc

5/ if I had only worked on a startup for a year, I would've gotten nowhere, the same way that if you lift for 3 months, it achieves nothing. Everything good in life comes from perseverance, but at the beginning, you're just like "I need to be somebody!!!"

Vibhu Vashisth
@VIBHU_Tweet

ANCIENT BHARAT WAS CALLED VISHWAGURU, AND IT REALLY DESERVED IT.

India had a well developed education system centuries before the westerners arrived and called us uncivilized. Education was always given a great importance in Indian civilisation since times immemorial.

Ancient India had the Gurukulas and Ashramas as the epicentres of the knowledge and enlightenment. Bigger Gurukulas served as the centres of higher education called universities. Besides these universities, temples also emerged as the major learning centres.

Studying the Holy Scriptures, character building, personality development, responsibilities towards self,family and society,discipline and preservation of the ancient culture and heritage were the key embodiments of education.

This kind of education system made ancient India, a centre of knowledge all over the world. Many foreign students came to India for education and India was called the 'Vishwaguru'.
Takshshila and Nalanda were the two prominent universities of ancient India.

But were these only Universities of ancient India?The answer is 'No'.Let's learn about these gems of our education system that flourished across ancient India & be proud.

NALANDA UNIVERSITY
This was the oldest university of ancient India.Situated in Nalanda distt. of Bihar...

Advertisement

Vibhu Vashisth
@VIBHU_Tweet

ARE WE FAMILIAR WITH THE MEANING & POWER OF MANTRAS WE CHANT?

Whenever we chant a Mantra in Sanskrit, it starts with 'Om' and mostly ends with 'Swaha' or 'Namaha'. This specific alignment of words has a specific meaning to it which is explained in Dharma Shastra.

Mantra is a Sanskrit word meaning sacred syllable or sacred word. But Mantras r not just words put together,they r also vibrations.The whole Universe is a cosmic energy in different states of vibration &this energy in different states of vibration forms the objects of Universe.

According to Scriptures,Om is considered to be ekaakshar Brahman,which means Om is the ruler of 3 properties of creator,preserver&destroyer which make the https://t.co/lyhkWeCdtv is also seen as a symbol of Lord Ganesha, as when starting the prayer,it's him who is worshipped 1st.

'Om' is the sound of the Universe. It's the first original vibration of the nothingness through which manifested the whole Cosmos. It represents the birth, death and rebirth process. Chanting 'Om' brings us into harmonic resonance with the Universe. It is a scientific fact.

Therefore, Mantras are described as vibrational words that are recited, spoken or sung and are invoked towards attaining some very specific results. They make very specific sounds at a frequency that conveys a directive into our subconcious.

$Sergio Mattei \u270c\ufe0f$

Sergio Mattei ✌️...
@matteing

With the coming challenge this week, I decided to compile a list of design resources all makers can use to spice up ✨ their projects! 😍

Thread 👇

🚨 DrawKit: Gorgeous, hand made illustrations by @JamesDaly90!

Also, one FREE custom illustration for all 24hrstartup

🙅‍♂️💩 @noshit_app: No shit - just great design resources! Find fonts, templates, and daily design inspiration. By maker @HarowitzBlack!

🛠 Figma: Visual mockup + prototyping tool. Make great mockups of your project!

💻

🤯 Digital Psychology: A great resource on how to design products that convert visitors to 🤑 sales. By maker @DaniStefanovic!

💻

Quinn Cummings
@quinncy

Gather round, Gentle Readers. It is time I tell the story of the worst decision I ever made in an office. Some of you have heard this. Some have not. Whatever you do in your office today, this week, the rest of this year, you can console yourself by recalling this tale.

A long time ago, I was a talent agent. I worked for a woman named Susan Smith, who had her own small boutique agency. She was known for three things:

1. She had fantastic taste in clients. If there is someone you admire, odds are good that at some point, she was their agent,

2. She could negotiate a deal like few who have ever trod the earth. Casting would give her all the money they had budgeted for that part, plus a little more, plus promising to get her dog Barnaby groomed. She was magnificent to watch.

3. She was insane.

I'm sure you're thinking, "Quinn, it's the entertainment industry, they are all insane." Yes, many are. So consider this; if you told someone you worked for Susan, people who worked for insane people would look and you and whisper, "I hear she's insane."