So I just installed Ubuntu, and this is my first time working in a Linux environment, so bear with my noobishness here.
所以我刚安装了Ubuntu，这是我第一次在Linux环境中工作，所以我要忍受我的noobi。
Anyway, I downloaded the Java 8 JDK directly from Oracle, but I understand there's also an OpenJDK for Java 8 as well. I have two questions.
无论如何，我直接从Oracle下载了Java 8 JDK，但是我知道Java 8也有一个OpenJDK。我有两个问题。
-
What is the difference between the Oracle version and OpenJDK. Pros/Cons?
Oracle版本和OpenJDK之间的区别是什么?优点/缺点?
-
When I try and get OpenJDK 8, I can't. I'm pasting the terminal command and the error message I get here, hoping for advice. Again, very new to Linux, been on my first Linux distro ever for less than an hour here at this point.
当我尝试使用OpenJDK 8时，我做不到。我正在粘贴终端命令和我到达这里的错误消息，希望得到建议。这是Linux的新版本，在我的第一个Linux发行版中，这是我在这一点上花了不到一个小时的时间。
user@computer:~/Java$ sudo apt-get install openjdk-8-jdk Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package openjdk-8-jdk
Any help would be appreciated. In the meantime, I'm just gonna use the Oracle package. Thanks.
如有任何帮助，我们将不胜感激。同时，我将使用Oracle包。谢谢。
Edit:
编辑:
So, now I have a new problem. I installed OpenJDK 7, it came with Maven and just installed before I realized I was getting a two-for-one deal. Now I have JDK 7, and Eclipse, and Maven, and they're all working, but I'm stuck on JDK 7 rather than 8.
现在我有了一个新问题。我安装了OpenJDK 7，它附带了Maven，并在我意识到我得到了一份两对一的协议之前安装了它。现在我有了JDK 7、Eclipse和Maven，它们都在工作，但是我被困在了JDK 7而不是8。
I saw that there's a link below, I intend to check it out in the morning, it's 2am and I'm tired right now. Any other advice for this new issue would be appreciated, otherwise I will definitely be checking out that link first thing in the morning.
我看到下面有个链接，我打算在早上查看一下，现在是凌晨2点，我现在很累。对于这个新问题的任何其他建议都将会得到赞赏，否则我肯定会在早上第一件事就是查看链接。
3 个解决方案
#1
83
UPDATE: installation without root privileges below
更新:没有根权限的安装。
I advise you to not install packages manually on ubuntu system if there is already a (semi-official) repository able to solve your problem. Further, use Oracle JDK for development, just to avoid (very sporadic) compatibility issues (i've tried many years ago, it's surely better now).
如果已经有一个(半官方的)存储库能够解决您的问题，我建议您不要在ubuntu系统上手动安装包。此外，使用Oracle JDK进行开发，只是为了避免(非常分散的)兼容性问题(我多年前尝试过，现在肯定更好了)。
Add the webupd8 repo to your system:
将webupd8 repo添加到您的系统:
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
Install your preferred version of jdk (versions from java-6 to java-9 available):
安装您首选的jdk版本(从java-6到java-9版本):
sudo apt-get install oracle-java8-installer
You can also install multiple version of jdk, mixing openjdk and oracle versions. Then you can use the command update-java-alternatives to switch between installed version:
您还可以安装多个版本的jdk，混合openjdk和oracle版本。然后，您可以使用命令update-java-替代品在已安装的版本之间切换:
# list available jdk
update-java-alternatives --list
# use jdk7
sudo update-java-alternatives --set java-7-oracle
# use jdk8
sudo update-java-alternatives --set java-8-oracle
Requirements
需求
If you get add-apt-repository: command not found be sure to have software-properties-common installed:
如果您获得了add-apt-repository:没有找到的命令一定要有软件属性—常见的安装:
sudo apt-get install software-properties-common
If you're using an older version Ubuntu:
如果你使用的是旧版本的Ubuntu:
sudo apt-get install python-software-properties
JDK installation without root privileges
没有根权限的JDK安装。
If you haven't administrator rights on your target machine your simplest bet is to use sdkman to install the zulu certified openjdk:
如果您的目标机器上没有管理员权限，那么最简单的方法就是使用sdkman安装zulu认证的openjdk:
curl -s "https://get.sdkman.io" | bash
source "$HOME/.sdkman/bin/sdkman-init.sh"
sdk install java
NOTE: sdkman allow to install also the official Oracle JDK, although it's not a the default option. View available versions with:
注意:sdkman允许安装官方的Oracle JDK，尽管它不是默认的选项。查看可用的版本:
sdk ls java
Install the chosen version with:
安装选择的版本:
sdk install java <version>
For example:
例如:
sdk install java 9.0.1-oracle
Glossary of commands
术语表的命令
-
sudo
<command> [command_arguments]: execute a command with the superuser privilege.sudo <命令> [command_arguments]:使用超级用户特权执行命令。
-
add-apt-repository
<PPA_id>: Ubuntu (just like every Debian derivatives and generally speaking every Linux distribution) has a main repository of packages that handle things like package dependencies and updating. In Ubuntu is possible to extend the main repository using a PPA (Personal Package Archive) that usually contains packages not available in the system (just like oracle jdk) or updated versions of available ones (example: LibreOffice 5 in LTS is available only through this PPA).扩展库
: Ubuntu(就像所有的Debian衍生工具，一般来说，每个Linux发行版)都有一个主要的包存储库，可以处理包依赖和更新之类的东西。在Ubuntu中，可以使用PPA(个人包存档)来扩展主存储库，它通常包含系统中不可用的包(就像oracle jdk一样)或更新版本的可用包(例如，LTS中的LibreOffice 5只能通过这个PPA提供)。 -
apt-get
[install|update|upgrade|purge|...]: it's "the" command-line package handler used to manipulate the state of every repository on the system (installing / updating / upgrading can be viewed as an alteration of the repository current state).apt-get[安装| | |清洗升级更新|…]:它是用于操作系统上每个存储库状态的“命令行包处理程序”(安装/更新/升级可以看作是对存储库当前状态的更改)。
In our case: with the command sudo add-apt-repository ppa:webupd8team/java we inform the system that the next repository update must retrieve packages information also from webupd8 repo.
在我们的示例中:使用命令sudo add-ap -repository ppa:webupd8team/java，我们通知系统，下一个储存库更新必须从webupd8 repo检索包信息。
With sudo apt-get update we actually update the system repository (all this operations requires superuser privileges, so we prepend sudo to the commands).
通过sudo apt-get更新，我们实际上更新了系统存储库(所有这些操作都需要超级用户权限，所以我们将sudo预加到命令中)。
sudo apt-get install oracle-java8-installer
sudo apt-get安装oracle-java8-installer
-
update-java-alternatives (a specific java version of update-alternatives): in Ubuntu several packages provides the same functionality (browse the internet, compile mails, edit a text file or provides java/javac executables...). To allows the system to choose the user favourites tool given a specific task a mechanism using symlinks under
/etc/alternatives/is used. Try to update the jdk as indicated above (switch between java 7 and java 8) and view how change the output of this command:update-java-替代品(一个特定的java版本的更新替代品):在Ubuntu中，几个包提供了相同的功能(浏览internet、编译邮件、编辑文本文件或提供java/javac可执行文件)。为了使系统能够选择用户喜爱的工具，给定一个特定的任务，在/etc/ options /下使用符号链接的机制。尝试按照上面的指示更新jdk(在java 7和java 8之间切换)，并查看如何更改此命令的输出:
ls -l /etc/alternatives/java*ls - l /etc/alternatives / java
In our case: sudo update-java-alternatives --set java-8-oracle update symlinks under /etc/alternatives to point to java-8-oracle executables.
在我们的例子中:sudo update-java- options——设置java-8-oracle更新在/etc/ options下的符号链接，以指向java-8-oracle可执行文件。
Extras:
附加功能:
-
man
<command>: start using man to read a really well written and detailed help on (almost) every shell command and its options (every command i mention in this little answer has a man page, tryman update-java-alternatives).man <命令> :开始使用man来阅读非常好的书面和详细的帮助(几乎)每个shell命令和它的选项(我在这个小回答中提到的每个命令都有一个man页面，try man update-java- options)。
-
apt-cache
search <search_key>: query the APT cache to search for a package related with the search_key provided (can be the package name or some word in package description).APT -cache搜索
:查询APT缓存，搜索与所提供的search_key相关的包(可以是包名称或包描述中的某个单词)。 -
apt-cache
show <package>: provides APT information for a specific package (package version, installed or not, description).APT -cache显示
:为特定的包提供APT信息(包版本，安装或不安装，描述)。
#2
61
As you can see I only have java 1.7 installed (on a Ubuntu 14.04 machine).
正如您所看到的，我只安装了java 1.7(在Ubuntu 14.04机器上)。
update-java-alternatives -l
java-1.7.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.7.0-openjdk-amd64
To install Java 8, I did,
为了安装Java 8，我做到了，
sudo add-apt-repository ppa:openjdk-r/ppa
sudo apt-get update
sudo apt-get install openjdk-8-jdk
Afterwards, now I have java 7 and 8,
之后，我有了java 7和8，
update-java-alternatives -l
java-1.7.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.7.0-openjdk-amd64
java-1.8.0-openjdk-amd64 1069 /usr/lib/jvm/java-1.8.0-openjdk-amd64
BONUS ADDED (how to switch between different versions)
额外添加(如何在不同版本之间切换)
- run the follwing command from the terminal:
- 从终端运行以下命令:
sudo update-alternatives --config javasudo update-alternatives——配置java
There are 2 choices for the alternative java (providing /usr/bin/java). Selection Path Priority Status ------------------------------------------------------------ 0 /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1071 auto mode 1 /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1071 manual mode * 2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1069 manual mode Press enter to keep the current choice[*], or type selection number:
As you can see I'm running open jdk 8. To switch to to jdk 7, press 1 and hit the Enter key. Do the same for javac as well with, sudo update-alternatives --config javac.
可以看到，我正在运行open jdk 8。切换到jdk 7，按1并按回车键。对javac和sudo update-替代品——config javac进行同样的操作。
Check versions to confirm the change: java -version and javac -version.
检查版本以确认更改:java版本和javac版本。
#3
12
I'm getting OpenJDK 8 from the official Debian repositories, rather than some random PPA or non-free Oracle binary. Here's how I did it:
我从官方的Debian存储库获得OpenJDK 8，而不是一些随机的PPA或非免费的Oracle二进制文件。我是这样做的:
sudo apt-get install debian-keyring debian-archive-keyring
sudo apt-get安装debian-keyring debian-archive-keyring。
Make /etc/apt/sources.list.d/debian-jessie-backports.list:
使/etc/apt/sources.list.d / debian-jessie-backports.list:
deb http://httpredir.debian.org/debian/ jessie-backports main
Make /etc/apt/preferences.d/debian-jessie-backports:
使/etc/apt/preferences.d / debian-jessie-backports:
Package: *
Pin: release o=Debian,a=jessie-backports
Pin-Priority: -200
Then finally do the install:
最后安装:
sudo apt-get update
sudo apt-get -t jessie-backports install openjdk-8-jdk
#1
83
UPDATE: installation without root privileges below
更新:没有根权限的安装。
I advise you to not install packages manually on ubuntu system if there is already a (semi-official) repository able to solve your problem. Further, use Oracle JDK for development, just to avoid (very sporadic) compatibility issues (i've tried many years ago, it's surely better now).
如果已经有一个(半官方的)存储库能够解决您的问题，我建议您不要在ubuntu系统上手动安装包。此外，使用Oracle JDK进行开发，只是为了避免(非常分散的)兼容性问题(我多年前尝试过，现在肯定更好了)。
Add the webupd8 repo to your system:
将webupd8 repo添加到您的系统:
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
Install your preferred version of jdk (versions from java-6 to java-9 available):
安装您首选的jdk版本(从java-6到java-9版本):
sudo apt-get install oracle-java8-installer
You can also install multiple version of jdk, mixing openjdk and oracle versions. Then you can use the command update-java-alternatives to switch between installed version:
您还可以安装多个版本的jdk，混合openjdk和oracle版本。然后，您可以使用命令update-java-替代品在已安装的版本之间切换:
# list available jdk
update-java-alternatives --list
# use jdk7
sudo update-java-alternatives --set java-7-oracle
# use jdk8
sudo update-java-alternatives --set java-8-oracle
Requirements
需求
If you get add-apt-repository: command not found be sure to have software-properties-common installed:
如果您获得了add-apt-repository:没有找到的命令一定要有软件属性—常见的安装:
sudo apt-get install software-properties-common
If you're using an older version Ubuntu:
如果你使用的是旧版本的Ubuntu:
sudo apt-get install python-software-properties
JDK installation without root privileges
没有根权限的JDK安装。
If you haven't administrator rights on your target machine your simplest bet is to use sdkman to install the zulu certified openjdk:
如果您的目标机器上没有管理员权限，那么最简单的方法就是使用sdkman安装zulu认证的openjdk:
curl -s "https://get.sdkman.io" | bash
source "$HOME/.sdkman/bin/sdkman-init.sh"
sdk install java
NOTE: sdkman allow to install also the official Oracle JDK, although it's not a the default option. View available versions with:
注意:sdkman允许安装官方的Oracle JDK，尽管它不是默认的选项。查看可用的版本:
sdk ls java
Install the chosen version with:
安装选择的版本:
sdk install java <version>
For example:
例如:
sdk install java 9.0.1-oracle
Glossary of commands
术语表的命令
-
sudo
<command> [command_arguments]: execute a command with the superuser privilege.sudo <命令> [command_arguments]:使用超级用户特权执行命令。
-
add-apt-repository
<PPA_id>: Ubuntu (just like every Debian derivatives and generally speaking every Linux distribution) has a main repository of packages that handle things like package dependencies and updating. In Ubuntu is possible to extend the main repository using a PPA (Personal Package Archive) that usually contains packages not available in the system (just like oracle jdk) or updated versions of available ones (example: LibreOffice 5 in LTS is available only through this PPA).扩展库
: Ubuntu(就像所有的Debian衍生工具，一般来说，每个Linux发行版)都有一个主要的包存储库，可以处理包依赖和更新之类的东西。在Ubuntu中，可以使用PPA(个人包存档)来扩展主存储库，它通常包含系统中不可用的包(就像oracle jdk一样)或更新版本的可用包(例如，LTS中的LibreOffice 5只能通过这个PPA提供)。 -
apt-get
[install|update|upgrade|purge|...]: it's "the" command-line package handler used to manipulate the state of every repository on the system (installing / updating / upgrading can be viewed as an alteration of the repository current state).apt-get[安装| | |清洗升级更新|…]:它是用于操作系统上每个存储库状态的“命令行包处理程序”(安装/更新/升级可以看作是对存储库当前状态的更改)。
In our case: with the command sudo add-apt-repository ppa:webupd8team/java we inform the system that the next repository update must retrieve packages information also from webupd8 repo.
在我们的示例中:使用命令sudo add-ap -repository ppa:webupd8team/java，我们通知系统，下一个储存库更新必须从webupd8 repo检索包信息。
With sudo apt-get update we actually update the system repository (all this operations requires superuser privileges, so we prepend sudo to the commands).
通过sudo apt-get更新，我们实际上更新了系统存储库(所有这些操作都需要超级用户权限，所以我们将sudo预加到命令中)。
sudo apt-get install oracle-java8-installer
sudo apt-get安装oracle-java8-installer
-
update-java-alternatives (a specific java version of update-alternatives): in Ubuntu several packages provides the same functionality (browse the internet, compile mails, edit a text file or provides java/javac executables...). To allows the system to choose the user favourites tool given a specific task a mechanism using symlinks under
/etc/alternatives/is used. Try to update the jdk as indicated above (switch between java 7 and java 8) and view how change the output of this command:update-java-替代品(一个特定的java版本的更新替代品):在Ubuntu中，几个包提供了相同的功能(浏览internet、编译邮件、编辑文本文件或提供java/javac可执行文件)。为了使系统能够选择用户喜爱的工具，给定一个特定的任务，在/etc/ options /下使用符号链接的机制。尝试按照上面的指示更新jdk(在java 7和java 8之间切换)，并查看如何更改此命令的输出:
ls -l /etc/alternatives/java*ls - l /etc/alternatives / java
In our case: sudo update-java-alternatives --set java-8-oracle update symlinks under /etc/alternatives to point to java-8-oracle executables.
在我们的例子中:sudo update-java- options——设置java-8-oracle更新在/etc/ options下的符号链接，以指向java-8-oracle可执行文件。
Extras:
附加功能:
-
man
<command>: start using man to read a really well written and detailed help on (almost) every shell command and its options (every command i mention in this little answer has a man page, tryman update-java-alternatives).man <命令> :开始使用man来阅读非常好的书面和详细的帮助(几乎)每个shell命令和它的选项(我在这个小回答中提到的每个命令都有一个man页面，try man update-java- options)。
-
apt-cache
search <search_key>: query the APT cache to search for a package related with the search_key provided (can be the package name or some word in package description).APT -cache搜索
:查询APT缓存，搜索与所提供的search_key相关的包(可以是包名称或包描述中的某个单词)。 -
apt-cache
show <package>: provides APT information for a specific package (package version, installed or not, description).APT -cache显示
:为特定的包提供APT信息(包版本，安装或不安装，描述)。
#2
61
As you can see I only have java 1.7 installed (on a Ubuntu 14.04 machine).
正如您所看到的，我只安装了java 1.7(在Ubuntu 14.04机器上)。
update-java-alternatives -l
java-1.7.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.7.0-openjdk-amd64
To install Java 8, I did,
为了安装Java 8，我做到了，
sudo add-apt-repository ppa:openjdk-r/ppa
sudo apt-get update
sudo apt-get install openjdk-8-jdk
Afterwards, now I have java 7 and 8,
之后，我有了java 7和8，
update-java-alternatives -l
java-1.7.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.7.0-openjdk-amd64
java-1.8.0-openjdk-amd64 1069 /usr/lib/jvm/java-1.8.0-openjdk-amd64
BONUS ADDED (how to switch between different versions)
额外添加(如何在不同版本之间切换)
- run the follwing command from the terminal:
- 从终端运行以下命令:
sudo update-alternatives --config javasudo update-alternatives——配置java
There are 2 choices for the alternative java (providing /usr/bin/java). Selection Path Priority Status ------------------------------------------------------------ 0 /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1071 auto mode 1 /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java 1071 manual mode * 2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1069 manual mode Press enter to keep the current choice[*], or type selection number:
As you can see I'm running open jdk 8. To switch to to jdk 7, press 1 and hit the Enter key. Do the same for javac as well with, sudo update-alternatives --config javac.
可以看到，我正在运行open jdk 8。切换到jdk 7，按1并按回车键。对javac和sudo update-替代品——config javac进行同样的操作。
Check versions to confirm the change: java -version and javac -version.
检查版本以确认更改:java版本和javac版本。
#3
12
I'm getting OpenJDK 8 from the official Debian repositories, rather than some random PPA or non-free Oracle binary. Here's how I did it:
我从官方的Debian存储库获得OpenJDK 8，而不是一些随机的PPA或非免费的Oracle二进制文件。我是这样做的:
sudo apt-get install debian-keyring debian-archive-keyring
sudo apt-get安装debian-keyring debian-archive-keyring。
Make /etc/apt/sources.list.d/debian-jessie-backports.list:
使/etc/apt/sources.list.d / debian-jessie-backports.list:
deb http://httpredir.debian.org/debian/ jessie-backports main
Make /etc/apt/preferences.d/debian-jessie-backports:
使/etc/apt/preferences.d / debian-jessie-backports:
Package: *
Pin: release o=Debian,a=jessie-backports
Pin-Priority: -200
Then finally do the install:
最后安装:
sudo apt-get update
sudo apt-get -t jessie-backports install openjdk-8-jdk