Time-Saving Tips and Tricks for Building Quality Java Applications

[CON5929]

Yusuke Yamamoto @yusuke

CON5929 #

Yusuke Yamamoto• Author of Samurai & Twitter4J • 16 years in Java industry

@yusuke@yusuke

http://junit.org/junit4/junit-lambda-contributors.html

���2:;/5:���%,)�"*%��&��

���

��$ *

���',&+"&!�� �

����� !�$

��� 346:������

28=7��,*+'% )��,((')+

��,�$"��� $�+"'&*��

9=16.<0���)# +"&!

���� - $'( )

.equals( )

Time-Saving Tips and Tricks for Building Quality Java Applications

Quality Aplication

#CON5929

Quality Application• Stable

• Performant

• Easy to understand

• Easy to fix

#CON5929

fewer bugs = !

can handle more requests = !

Code Review Test Deploy Fail Fix

Code Review Test Deploy Fail Fix

"

"

Code quickly

Code Review Test Deploy

Code Review Test Deploy

Code quicklyUse appropriate tool / IDE

Code

#CON5929

completion generation inspection

demoUsing Twitter4J

- retrieve my home timeline

- print status text with @username only if the user is not @yusuke

#CON5929

Help > Productivity Guide

Review quickly

Code Review Test Deploy

Code Review Test Deploy

Review on IDEDo Code reviews on IDE, NOT on browser

you cannot trace references / definitions

#CON5929

Review on IDE #CON5929

,or use Upsource

Test quickly

Code Review Test Deploy

Code Review Test Deploy

Test UI as well as business logic• UI tend to break easier

• More automated UI tests

• Less manual UI tests

Selenium• automated UI testing tool

http://www.seleniumhq.org

WebDriver driver = new FirefoxDriver(); driver.get("https://www.google.com/"); WebElement element = driver.findElement(By.className("gsfi")); element.click(); element.sendKeys("JavaOne 2016"); driver.findElement(By.name("btnK")).click(); Thread.sleep(100000);

Selenide

http://selenide.org

WebDriver driver = new FirefoxDriver(); driver.get("https://www.google.com/"); WebElement element = driver.findElement(By.className("gsfi"));element.click(); element.sendKeys("JavaOne 2016"); driver.findElement(By.name("btnK")).click();Thread.sleep(100000);

Navigator navigator = new Navigator(); navigator.open("https://www.google.com/");$(".gsfi").click(); $(".gsfi").sendKeys("JavaOne 2016"); $("[name='btnK']").click();

http://phantomjs.org

How to use

1. Download, and Unpack zip 2. Set system properties properly

System.setProperty("phantomjs.binary.path", "path/to/phantomjs"); System.setProperty("browser", "phantomjs");

How to use

3. Add dependency to your project

<dependency> <groupId>com.codeborne</groupId> <artifactId>phantomjsdriver</artifactId> <version>1.2.1</version> </dependency>

How to use

4. You're good to goWebDriver driver = new PhantomJSDriver(); driver.get("https://www.google.com/");WebElement element = driver.findElement(By.className("gsfi")); element.click();element.sendKeys("JavaOne 2016");driver.findElement(By.name("btnK")).click();

PhantomJSInstallerCheck PhantomJS Installation

Download, unpack, install automatically

#CON5929

yusuke/javaone2016demo

Do not boot container every time.

Use existing container process if available.

Test quicklyDo not boot container every time.

Use existing container process if available.

#CON5929

Test quickly #CON5929

TestCase Container Test Targetboot

instantiate

GET / HTTP/1.0 … method()

Skip booting the container1. Check the container availability.

2. Boot one only when necessary.

3. Test

Test quickly #CON5929

TestCase Container Test Target

GET / HTTP/1.0 … method()check availability

Deploy quickly

Code Review Test Deploy

Code Review Test Deploy

Start & Redeploy quickly

-Xverify:none

Disables byte code verification.

-XX:TieredStopAtLevel=1

Time to startup with/witout optionsse

cond

s

2.0

3.0

4.0

5.0

6.0

7.0

8.0

default-Xverify:none-XX:TieredStopAtLevel=1-XX:TieredStopAtLevel=1 -Xverify:none

default: 7.13 secs

-Xverify:none: 6.17 secs

-XX:TieredStopAtLevel=1: 4.55 secscombined: 4.00 secs

53% faster

HotSwap

#CON5929

HotSwap

• JVM built-in feature

• Reloads class changes on the fly

• Available only in debug session

HotSwap

HotSwap limitation

• applicable only for method body changes

Unlimited dynamic swap

http://zeroturnaround.com/software/jrebel/

yusuke/javaone2016demo

#CON5929