Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Fundamental Java
Search
HASUNUMA Kenji
April 20, 2016
Programming
37
0
Share
Fundamental Java
HASUNUMA Kenji
April 20, 2016
More Decks by HASUNUMA Kenji
See All by HASUNUMA Kenji
Jakarta EE: The First Parts
khasunuma
0
55
Life of our small product
khasunuma
0
45
How to adapt MicroProfile API for generic Web applications
khasunuma
0
41
Overviewing Admin Console
khasunuma
0
40
Introduction to MicroProfile Metrics
khasunuma
0
63
Basic method for Java EE Web Profile
khasunuma
0
38
Introduction to JCA and MDB
khasunuma
0
91
Collections Framework Begineers Guide 2
khasunuma
0
80
JLS myths ~ if-then-else statement ~
khasunuma
0
46
Other Decks in Programming
See All in Programming
Tamach-sre-3_ANDPAD-shimaison93
mane12yurks38
0
240
Codex CLIのSubagentsによる並列API実装 / Parallel API Implementation with Codex CLI Subagents
takatty
2
780
生成 AI 時代のスナップショットテストってやつを見せてあげますよ(α版)
ojun9
0
340
Kubernetesでセルフホストが簡単なNewSQLを求めて / Seeking a NewSQL Database That's Simple to Self-Host on Kubernetes
nnaka2992
0
190
メッセージングを利用して時間的結合を分離しよう #phperkaigi
kajitack
3
540
最初からAWS CDKで技術検証してもいいんじゃない?
akihisaikeda
4
180
存在論的プログラミング: 時間と存在を記述する
koriym
5
760
Nuxt Server Components
wattanx
0
240
仕様漏れ実装漏れをなくすトレーサビリティAI基盤のご紹介
orgachem
PRO
8
4.2k
AWS×クラウドネイティブソフトウェア設計 / AWS x Cloud-Native Software Design
nrslib
16
3.5k
それはエンジニアリングの糧である:AI開発のためにAIのOSSを開発する現場より / It serves as fuel for engineering: insights from the field of developing open-source AI for AI development.
nrslib
1
820
Strategy for Finding a Problem for OSS: With Real Examples
kibitan
0
130
Featured
See All Featured
[SF Ruby Conf 2025] Rails X
palkan
2
880
Kristin Tynski - Automating Marketing Tasks With AI
techseoconnect
PRO
0
210
Building an army of robots
kneath
306
46k
Agile Actions for Facilitating Distributed Teams - ADO2019
mkilby
0
170
A brief & incomplete history of UX Design for the World Wide Web: 1989–2019
jct
1
340
Navigating Algorithm Shifts & AI Overviews - #SMXNext
aleyda
1
1.2k
[RailsConf 2023] Rails as a piece of cake
palkan
59
6.4k
Visualization
eitanlees
150
17k
Optimising Largest Contentful Paint
csswizardry
37
3.6k
Chasing Engaging Ingredients in Design
codingconduct
0
160
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
508
140k
Tell your own story through comics
letsgokoyo
1
880
Transcript
Fundamental Java HASUNUMA Kenji Vice president, GlassFish Users Group Japan
[email protected]
Twitter: @btnrouge
What’s Java?
Javaͷಛ • Φʔϓϯͳن֨Ͱ͋Δ • ৗʹਐԽ͍ͯ͠Δ • ޓੑΛॏࢹ͍ͯ͠Δ
JavaΦʔϓϯن֨ • ݴޠɺඪ४APIɺԾϚγϯ༷ • Java Community ProcessͰඪ४Խ • ݱࡏΦʔϓϯιʔε (GPLv2)
wWrite Once, Run Anywhere wݴޠϨϕϧͰϚϧνεϨουରԠ wݫ֨ͳྫ֎ॲཧػߏ w6OJDPEFΛશ໘తʹ࠾༻
Write Once, Run Anywhere • OSɺJava VM࣮ʹґଘ͠ͳ͍ • ݹ͍ίʔυ͕࠷৽ͷJavaͰಈ͘ •
Blu-ray͔ΒڊେγεςϜ·Ͱ
ॳ04ͷࠩҟΛ+BWB7.͕ٵऩ͢Δ ݱࡏ+BWB7.͕ଟݴޠͷڞ௨ج൫
Essential Java
JavaͷΤίγεςϜ
ΫϥεͱΠϯλϑΣʔε
!
! Ϋϥεͷܧঝ
" #
" Polymorphismͱ
$%& '&( ( )&%%%
ϓϩηεͱεϨου
$%& '&( ( )&%%%
$%* $%* $%* + + ϓϩηεͱεϨου
, "- # ./0 , 0 #- ./0 " " " " " " -""1 +BWBͷೖग़ྗ 4USFBN ݱࡏͰจࣈྻσʔλʹಛԽͨ͠3FBEFS8SJUFSɺ ߴ*0Λ࣮ݱ͢Δ$IBOOFMΑ͘ΘΕ͍ͯΔ
+BWBͷύοέʔδ
Ϋϥε໊ͷදهํ๏ wݪଇύοέʔδΛؚΉશ໊ ྫ java.util.List wimportએݴಛఆͷύοέʔδΛলུՄ ํ๏ import java.util.List; ํ๏ import
java.util.*; wjava.langʜৗʹύοέʔδΛলུՄ
+BWBΫϥεͷಉҰੑ • Ϋϥε໊͕ಉҰͰ͋Δ • ύοέʔδ໊͕શʹҰக͍ͯ͠Δ • ಉ͡Ϋϥεϩʔμʔ͔ΒಡΈࠐ·Εͨ
Java Core Parts
ΫϥεͱΦϒδΣΫτ • ΫϥεఆٛͷΈ…࣮ମ͕ͳ͍ • ΦϒδΣΫτ(Πϯελϯε) …Ϋϥε͔Β࡞࣮ͨ͠ମͷ͜ͱ • ϑΟʔϧυͱϝιουΦϒδΣΫτʹ ଐ͢Δ(㱻staticΫϥεʹଐ͢Δ)
java.lang.Object • JavaͷશΫϥεͷεʔύʔΫϥε • ΫϥεͷࠜװʹؔΘΔϝιουΛ࣋ͭ • ϓϦϛςΟϒܕʹରͯ͠ϦϑΝϨϯεܕ ͱݺΕΔ͜ͱ͋Δ
java.lang.Object ͷϝιου equals ಉҰνΣοΫʹ͏ ※ݪଇͱͯ͠ΦʔόʔϥΠυ͢Δ hashCode toString จࣈྻදݱΛฦ͢ ※༻్༷ʑ wait
εϨου੍ޚ༻ϝιου ※௨ৗConcurrency UtilitiesΛܦ༝ ͯ͠༻͢Δ(ΦʔόʔϥΠυෆՄ) notify notifyAll clone ίϐʔ(࠷ۙΘΕͳ͍) finalize ޙॲཧ(௨ৗΦʔόʔϥΠυ͠ͳ͍)
Object o = new Object();
Object o = new Object();
Object o = new Object(); ӈลͱಉ͡Ϋϥε PS εʔύʔΫϥε PS ࣮ΠϯλϑΣʔε
Object o = new ArrayList();
Ωϟετ Object o = new ArrayList(); • objͷఆٛObjectɺ࣮ମArrayList • ΞΫηεఆٛΛ௨ͯ͡ߦ͏
• ࣮ମͷΞΫηεˠΩϟετ ArrayList list = (ArrayList) o; w Ωϟετ=αϒΫϥεͷఆٛͰΞΫηε w Ωϟετޙ࣮ମʹΞΫηεՄೳ
ϓϦϛςΟϒܕ • ΫϥεͰͳ͍σʔλܕ • ରԠ͢ΔΫϥε(ϥούʔ)Λ࣋ͭ • auto-boxing/unboxing: ϓϦϛςΟϒܕͱϥούʔͷ૬ޓม
ϓϦϛςΟϒܕ ϥούʔΫϥε boolean Boolean byte Byte char Character short Short
int Integer long Long float Float double Double
ྻ • ಉ͡ΫϥεorϓϦϛςΟϒܕͷ࿈ଓ • ԋࢉࢠ [ ] ͰཁૉʹΞΫηε͢Δ • ෦తʹjava.lang.ArrayΫϥε
Object[ ] o = new Object[8]; P0CKFDUͷྻ ཁૉࢦఆ͠ͳ͍ ྻͷཁૉ ඞͣఆޙͰมߋෆՄ
ྻͷ߹ɺࠨลͱӈลಉ͡Ϋϥε
ͦͷଞͷॏཁͳτϐοΫ • Generics (J2SE 5.0) • Annotation (J2SE 5.0) •
Project Coin (Java SE 7) • Collections Framework (J2SE 1.2) • New I/O (J2SE 1.4 & Java SE 7) • Concurrency Utilitites (J2SE 5.0 & Java SE 7)
Fundamental Java HASUNUMA Kenji
[email protected]
Twitter: @btnrouge