Installing Java

From Funtoo
Revision as of 19:02, 27 October 2013 by Duncan.Britton (Talk | contribs)

Jump to: navigation, search

Contents

What is Java? What purpose does it serve?

Definition

"Java is a computer programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another. " ([en.wikipedia.org/wiki/Java_(programming_language) Wikipedia entry])

Installing java

Editing your make.conf

To tell portage that we would like it to pull java in the next time it is updated, we need to do the following:

 # nano /etc/portage/make.conf

Running that command should present you with a file containing something similar to this:

File:Make conf example.png
An example make.conf

In the file, if it does not exist, create a line like the following:

USE="java"

Press Ctrl+X , then y, then enter to write the changes to the file.

Emerging java

To install java, run the following command:

 # emerge --ask --update --newuse --deep @world

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] dev-java/java-config-wrapper-0.16  8 kB
[ebuild  N     ] sys-apps/baselayout-java-0.1.0  71 kB
[ebuild  N     ] dev-java/java-config-2.2.0-r1000:2  PYTHON_ABIS="2.7 3.3 -2.6 -3.1 -3.2 (-3.4)" 51 kB
[ebuild  N     ] app-admin/eselect-java-0.1.0  71 kB
[ebuild  N     ] dev-java/icedtea-bin-7.2.3.9:7  USE="X alsa cups -cjk -doc -examples -nsplugin -source" 47,781 kB
[ebuild  N     ] virtual/jdk-1.7.0:1.7  0 kB
[ebuild  N     ] virtual/jre-1.7.0:1.7  0 kB
Would you like to merge these packages? [Yes/No] yes

Testing to see if it emerged

To check that java installed on your system, run the following command:

java -version

If you get something like this, you are ready to use java!:

java version "1.7.0_21"OpenJDK Runtime Environment (IcedTea 2.3.9) (Gentoo build 1.7.0_21-b02)OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)

Usin the JDK and JRE

Launching a jar file

To run a .jar file with java , do the following:

 # java -jar <insert jarfile name here>