Deepin System Manual Installation Oracle Jdk8 detailed tutorials

Deepin System Manual Installation Oracle Jdk8 detailed tutorials

Download the JDK archive from Oracle website and extract the files using sudo tar-zxf jdk***, which I placed under the HOME/DIY/JAVA/JDK path.

JDK file path:/home/diy/java/jdk/jdk1.8.0_152

JDK environment variable Configuration

Modifying a configuration file

sudo vi/etc/profile

After entering, knock on I, then you can edit the content.

Add content at the end of a file

Java_home=/home/diy/java/jdk/jdk1.8.0_152

Classpath=/home/diy/java/jdk/jdk1.8.0_152/lib

Path= $PATH: $JAVA _home/bin: $CLASSPATH

Export PATH

Use ESC, then enter: Wq, save exit

To make the configuration effective, command-side input:

Source/etc/profile

Configuring the default JDK

Create a new Java version

Create a new system command link in the shell with the update-alternatives command:

sudo update-alternatives--install/usr/bin/javac Javac/home/diy/java/jdk/jdk1.8.0_152/bin/javac 1171

sudo update-alternatives--install/usr/bin/java Java/home/diy/java/jdk/jdk1.8.0_152/bin/java 1171

sudo update-alternatives--install/usr/bin/jar Jar/home/diy/java/jdk/jdk1.8.0_152/bin/jar 1171

sudo update-alternatives--install/usr/bin/javah javah/home/diy/java/jdk/jdk1.8.0_152/bin/javah 1171

sudo update-alternatives--install/usr/bin/javap javap/home/diy/java/jdk/jdk1.8.0_152/bin/javap 1171

Update-alternatives is a tool dedicated to maintaining system command links in the Ubuntu system, with the following 1171 being used to specify the priority of the current link, and the highest priority will automatically be set to the default version.

You can use the following command to view the version and priority of Java:

Update-alternatives--display Java

Choose the version of Java

Execute command

Update-alternatives--config Java

Output

There are 2 candidates that can be used to replace Java (providing/usr/bin/java).

Select Path Priority state

------------------------------------------------------------

* 0/usr/lib/jvm/jdk1.7.0_79/bin/java 1171 Auto mode

1/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 Manual Mode

2/usr/lib/jvm/jdk1.7.0_79/bin/java 1171 Manual Mode

You can see that the JDK that you just configured has a 1.7 priority configuration of 1171, which is higher than the original 1081, so it is automatically set to default.

Test

View Java version

Execute the following command on the shell

Java-version

If you get the following output, it proves that the JDK has successfully installed the configuration.

Picked up _java_options:-dawt.usesystemaafontsettings=gasp

Java Version "1.8.0_152"

Java (TM) SE Runtime Environment (build 1.8.0_152-B16)

Java HotSpot (TM) 64-bit Server VM (build 25.152-b16, Mixed mode)

If the Tomcat folder is not recognized when you encounter Eclipse configuration Tomcat8, the reference may be a file permission issue:

-R recursively perform an operation, whether deleting a folder or modifying all file permissions under a folder

Permissions change, 777 equals Full Control permissions:

Change permissions for a folder or file: chmod 777 file path/file name

To change permissions for all files under a folder: sudo chmod-r 777 folder

Deepin System Manual Installation Oracle Jdk8 detailed tutorials