【移動應(yīng)用開發(fā)技術(shù)】Java8精簡的JRE舉例分析

【移動應(yīng)用開發(fā)技術(shù)】Java8精簡的JRE舉例分析

這篇文章主要介紹“Java8精簡的JRE舉例分析”，在日常操作中，相信很多人在Java8精簡的JRE舉例分析問題上存在疑惑，在下查閱了各式資料，整理出簡單好用的操作方法，希望對大家解答”Java8精簡的JRE舉例分析”的疑惑有所幫助！接下來，請跟著在下一起來學(xué)習(xí)吧！1.更小的Java環(huán)境需要更少的計(jì)算資源。2.一個較小的運(yùn)行時環(huán)境可以更好的優(yōu)化性能和啟動時間。3.消除未使用的代碼從安全的角度總是好的。4.這些打包的應(yīng)用程序可以下載速度更快。緊湊的JRE分3種，分別是compact1、compact2、compact3，他們的關(guān)系是compact1<compact2<compact3,他們包含的API如下圖所示javac–bootclasspath,or

javac–profile<profile>如果不符合compact的api，則報錯。?12345678$

javac

-profile

compact2

Test.javaTest.java:7:

error:

ThreadMXBean

is

not

available

in

profile

'compact2'

ThreadMXBean

bean

=

ManagementFactory.getThreadMXBean();

^Test.java:7:

error:

ManagementFactory

is

not

available

in

profile

'compact2'

ThreadMXBean

bean

=

ManagementFactory.getThreadMXBean();

^2

errorsjava8新增一個工具，用來分析應(yīng)用程序所依賴的profile，有三個參數(shù)比較常用-p，-v，-r?123456789import

java.util.Set;import

java.util.HashSet;

public

class

Deps

{

public

static

void

main(String[]

args)

{

System.out.println(Math.random());

Set<String>

set

=

new

HashSet<>();

}}?12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061**************

PROFILE

********************jdeps

-P

Deps.class

Deps.class

->

/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/rt.jar

<unnamed>

(Deps.class)

->

java.io

compact1

->

java.lang

compact1

->

java.util

compact1

**************

VERBOSE

********************jdeps

-v

Deps.class

Deps.class

->

/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/rt.jar

Deps

(Deps.class)

->

java.io.PrintStream

->

java.lang.Math

->

java.lang.Object

->

java.lang.String

->

java.lang.System

->

java.util.HashSet

**************

RECURSIVE

********************jdeps

-R

Deps.class

Deps.class

->

/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/rt.jar

<unnamed>

(Deps.class)

->

java.io

->

java.lang

->

java.util

/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/jce.jar

->

/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/rt.jar

javax.crypto

(jce.jar)

->

java.io

->

java.lang

->

java.lang.reflect

->

->

java.nio

->

java.security

->

java.security.cert

->

java.security.spec

->

java.util

->

java.util.concurrent

->

java.util.jar

->

java.util.regex

->

java.util.zip

->

javax.security.auth

->

sun.security.jca

JDK

internal

API

(rt.jar)

->

sun.security.util

JDK

internal

API

(rt.jar)

->

sun.security.validator

JDK

internal

API

(rt.jar)

erfaces

(jce.jar)

->

java.lang

->

java.math

->

java.security

javax.crypto.spec

(jce.jar)

->

java.lang

->

java.math

->

java.security.spec

->

java.util

/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/rt.jar

->

/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre/lib/jce.jar

java.security

(rt.jar)

->

javax.crypto

JDK

internal

API

(jce.jar)

sun.security.util

(rt.jar)

->

javax.crypto

JDK

internal

API

(jce.jar)

->

erfaces

JDK

internal

API

(jce.jar)

->

javax.crypto.spec

JDK

internal

API

(jce.jar)?1234567891011121314151617181920212223$

hg

clone

/jdk8/jdk8/$

cd

jdk8$

make

images

profiles

:

##

Finished

profiles

(build

time

00:00:27)

Build

times

Start

2013-03-17

14:47:35End

2013-03-17

14:58:2600:00:25

corba00:00:15

demos00:01:50

hotspot00:00:24

images00:00:21