Java程序辅导

˜Cardiff University
School of Computer Science & Informatics
Ysgol Cyfrifiadureg a Gwybodeg
Prifysgol Caerdydd
Introductory Note 610
Choosing Java 6, 7 or 8 on Linux
Robert Evans
16th September, 2014
Copyright c©2014 Robert Evans.
Email: Robert.Evans@cs.cardiff.ac.uk
Abstract
The Linux Mint 13 workstations in the School’s Open Source Software Labora-
tory have Java versions 6, 7 and 8 installed.
Java 7 is the default. This Note tells you how to opt for a different version of
Java.
Contents
1 Java in the Linux Lab 2
1.1 Using other versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Computer Science & Informatics: Introductory Note 610
1 Java in the Linux Lab
The Linux Mint 13 workstations in the School’s Open Source Software Laboratory
have Java versions 6, 7 and 8 installed.
By default the version of Java that runs in the Lab is Oracle Java 7.
$ java -version
java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)
1.1 Using other versions
You can choose to use Java 6 or Java 8 in a terminal session by issuing a usejava
command.
To use Java 6 –
$ usejava6
Now all subsequent Java commands in the terminal, and applications which use Java
that are started in the terminal window, will use Sun Java 6.
$ java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02, mixed mode)
To use Java 8 –
$ usejava8
Now all subsequent Java commands in the terminal, and applications which use Java
that are started in the terminal window, will use Oracle Java 8.
$ java -version
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)
If you use other terminal windows, or applications started from the program menu, the
they will continue to use Java 7.