Some recommended books for improving as a software developer
Most software books are too language specific and go out of date too quickly. What I find has stayed with me are books about bigger concepts, such as systems thinking and complexity, and also so-called "soft skills" such as management and psychology.
These are all really about developing empathy for other people :)
| # LMF class generated at runtime, dumped via | |
| # <Scala 2.12.2>/bin/scala -cp . -Djdk.internal.lambda.dumpProxyClasses=dumpclasses Bar | |
| $ javap -verbose -private -c -s -l 'Bar$$$Lambda$101.class' | |
| Classfile /private/tmp/dumpclasses/Bar$$$Lambda$101.class | |
| Last modified Apr 30, 2020; size 695 bytes | |
| MD5 checksum 419f2634b1acdf7f40ba0bb7c22eabf4 | |
| final class Bar$$$Lambda$101 implements scala.runtime.java8.JFunction0$mcV$sp,scala.Serializable | |
| minor version: 0 | |
| major version: 52 |
国内从 Docker Hub 拉取镜像有时会遇到困难，此时可以配置镜像加速器。Docker 官方和国内很多云服务商都提供了国内加速器服务。
Dockerized 实践 https://github.com/y0ngb1n/dockerized
Ubuntu 16.04+、Debian 8+、CentOS 7+
I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.
This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea
Microsoft partnered with Canonical to create Bash on Ubuntu on Windows, running through a technology called the Windows Subsystem for Linux. Below are instructions on how to set up the ssh server to run automatically at boot.
/etc/ssh/sshd_config file by running the command sudo vi /etc/ssh/sshd_config and do the following
Port to 2222 (or any other port above 1000)PasswordAuthentication to yes. This can be changed back to no if ssh keys are setup.sudo service ssh --full-restart
Scala provides many tools to help us build programs with less runtime errors.
Instead of relying on nulls, the recommended practice is to use the Option type.
Instead of throwing exceptions, Try and Either types are used for representing potential error scenarios.
What’s common with these features is that they’re used for capturing runtime features in the type system,
thus lifting the runtime scenario handling to the compilation phase:
your program doesn’t compile until you’ve explicitly handled nulls, exceptions, and other runtime features in your code.
In his “Strategic Scala Style” blog post series,
| object Main extends App { | |
| AvoidLosingGenericType.run() | |
| AvoidMatchingOnGenericTypeParams.run() | |
| TypeableExample.run() | |
| TypeTagExample.run() | |
| } | |
| class Funky[A, B](val foo: A, val bar: B) { | |
| override def toString: String = s"Funky($foo, $bar)" | |
| } |
| package object mail { | |
| implicit def stringToSeq(single: String): Seq[String] = Seq(single) | |
| implicit def liftToOption[T](t: T): Option[T] = Some(t) | |
| sealed abstract class MailType | |
| case object Plain extends MailType | |
| case object Rich extends MailType | |
| case object MultiPart extends MailType |
| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
| #!/bin/sh | |
| exec /Users/sroebuck/local/bin/scalas $0 $@ | |
| !# | |
| /*** | |
| libraryDependencies ++= Seq( | |
| "com.github.scala-incubator.io" %% "scala-io-file" % "0.2.0", | |
| "joda-time" % "joda-time" % "2.0", | |
| "org.joda" % "joda-convert" % "1.1" | |
| ) | |
| */ |