/[gentoo]/xml/htdocs/doc/en/java.xml
Gentoo

Diff of /xml/htdocs/doc/en/java.xml

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

Revision 1.1 Revision 1.34
1<?xml version='1.0'?> 1<?xml version="1.0" encoding="UTF-8"?>
2<?xml-stylesheet href="/xsl/guide.xsl" type="text/xsl"?> 2<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/java.xml,v 1.34 2006/10/08 22:52:16 nightmorph Exp $ -->
3<guide> 3<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
4
5<guide link="/doc/en/java.xml">
4<title>Gentoo Java Guide</title> 6<title>Gentoo Java Guide</title>
7
5<author title="Author and Editor"> 8<author title="Author">
6<mail link="karltk@gentoo.org">Karl Trygve Kalleberg</mail> 9 <mail link="nichoj@gentoo.org">Joshua Nichols</mail>
7</author> 10</author>
11<author title="Author">
12 <mail link="karltk@gentoo.org">Karl Trygve Kalleberg</mail>
13</author>
14<author title="Editor">
15 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
16</author>
8 17
9<abstract> 18<abstract>
10Users' and Developers' Guide to Java in Gentoo 19This guide will introduce you to Java and explain how to use Java with Gentoo
20Linux.
11</abstract> 21</abstract>
12 22
23<!-- The content of this document is licensed under the CC-BY-SA license -->
24<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
25<license/>
26
13<version>0.1.1</version> 27<version>0.10</version>
14<date>June 25, 2002</date> 28<date>2006-10-08</date>
15 29
16<chapter> 30<chapter>
17 31<title>What is Java?</title>
18<title>Installing a JDK/JRE</title>
19<section> 32<section>
20<title>Overview</title> 33<title>Overview</title>
21<body> 34<body>
22<p>Gentoo provides numerous JDKs and JREs. The default is the
23Blackdown JDK/JRE pair, as it is freely (beer) available without any
24registration fuss.</p>
25 35
26<note>As kaffe becomes a JRE/JDK drop-in replacement, that will most 36<p>
27likely become our default.</note> 37Java is a programming language developed by engineers of Sun Microsystems. The
38language is object-oriented and designed to run on multiple platforms without
39the need of recompiling code for each platform. Although Java can be compiled
40as a native program, much of Java's popularity can be attributed to its
41portability, along with other features such as garbage collection. To make
42platform independence possible the Java compiler compiles the Java code to an
43intermediate representation called "Java bytecode" that runs on a JRE (Java
44Runtime Environment) and not directly on the operating system.
45</p>
28 46
29<p>Both the Sun JDK/JRE and the IBM JDK/JRE are generally faster, but 47<p>
30getting them is a bit more work, as you are required to read and 48In order to run Java bytecode, one needs to have a JRE (Java Runtime
31accept their license before downloading (IBM additionally requires you 49Environment) installed. A JRE provides core libraries, a platform dependent
32to register).</p> 50Java Virtual Machine, plug-ins for browsers, among other things. A JDK (Java
51Development Kit) adds programming tools, such as a bytecode compiler and a
52debugger.
53</p>
33 54
34<p>Our ebuilds for the Sun and IBM JDK/JREs will notify you of where
35to go to download them.</p>
36</body> 55</body>
37</section>
38
39<section> 56</section>
40<title>Installing the Sun/IBM JDK/JREs</title> 57</chapter>
58
59<chapter>
60<title>New Java System</title>
61<section>
62<body>
63
64<p>
65The way Java is handled on Gentoo has recently seen many changes and
66improvements. This has only happened very recently, and as a result, all the
67packages related to it are marked with testing keywords, ie ~x86. This
68document assumes you are using the new system.
69</p>
70
41<body> 71</body>
42<p>If you run <c>emerge dev-java/sun-jdk-1.3.1</c> or <c>emerge 72</section>
43dev-java/ibm-jdk-1.3.1</c>, you will be notified that you are required 73<section>
44to download the actual tarballs yourself. This has to do with license 74<title>Keywords</title>
45restrictions for the Sun JDK/JRE (online click-wrap license) and 75<body>
46registration issues with the IBM JDK/JRE.</p>
47 76
48<note>There is also a dev-java/sun-jdk-1.4.0, but not all packages 77<p>
49work nicely with Java 1.4, so you're on your own if you use the 1.4.0 78If you are using the stable tree opposed to ~arch, you will need to add some
79entries to your <path>/etc/portage/package.keywords</path>:
80</p>
81
82<pre caption="package.keywords">
83# Core Gentoo/Java Packages
84dev-java/ant-core
85dev-java/ant-tasks
86dev-java/ant
87dev-java/java-config
88dev-java/java-config-wrapper
89dev-java/javatoolkit
90dev-java/sun-jce-bin
91# JDKs
92=dev-java/sun-jdk-1.4*
93=dev-java/sun-jdk-1.5*
94=dev-java/ibm-jdk-bin-1.4*
95=dev-java/ibm-jdk-bin-1.5*
96=dev-java/jrockit-jdk-bin-1.4*
97=dev-java/jrockit-jdk-bin-1.5*
98=dev-java/blackdown-jdk-1.4*
99dev-java/kaffe
100# JREs
101=dev-java/sun-jre-bin-1.4*
102=dev-java/sun-jre-bin-1.5*
103=dev-java/ibm-jre-bin-1.4*
104=dev-java/blackdown-jre-1.4*
105# Virtuals
106virtual/jdk
107virtual/jre
108# Compilers
109dev-java/eclipse-ecj
110dev-java/jikes
111# Documentation
112dev-java/java-sdk-docs
113# Misc packages that have been updated to generation-2,
114# where the generation-1 won't build and/or run properly
115dev-java/lucene
116# These have optional Java support, but need ~arch to function properly
117# with generation-2
118dev-util/subversion
119sys-libs/db
120</pre>
121
122<warn>
123It is crucial that you list ALL these packages in
124<path>/etc/portage/package.keywords</path>, otherwise you will have problems in
125the later steps of this guide. Your new Java system will not function correctly
126without this list.
127</warn>
128
129</body>
130</section>
131<section>
132<title>Existing installs</title>
133<body>
134
135<p>
136For existing installs, regardless of if you have installed anything Java
137before, make sure you have followed the <uri
138link="/proj/en/java/java-upgrade.xml">Java Upgrade Guide</uri>.
139</p>
140
141</body>
142</section>
143<section>
144<title>New installs</title>
145<body>
146
147<p>
148New installs should require no further preparation.
149</p>
150
151</body>
152</section>
153</chapter>
154
155<chapter>
156<title>Installing a Virtual Machine</title>
157<section>
158<title>The choices</title>
159<body>
160
161<p>
162Gentoo provides numerous Runtime Environments (JREs) and Development Kits
163(JDKs). Among the current choices, we have:
164</p>
165
166<table>
167<tr>
168 <th>Vendor</th>
169 <th>JDK</th>
170 <th>JRE</th>
171</tr>
172<tr>
173 <ti>The Blackdown Java Kit</ti>
174 <ti>dev-java/blackdown-jdk</ti>
175 <ti>dev-java/blackdown-jre</ti>
176</tr>
177<tr>
178 <ti>Sun's Java Kit</ti>
179 <ti>dev-java/sun-jdk</ti>
180 <ti>dev-java/sun-jre-bin</ti>
181</tr>
182<tr>
183 <ti>The IBM Java Kit</ti>
184 <ti>dev-java/ibm-jdk-bin</ti>
185 <ti>dev-java/ibm-jre-bin</ti>
186</tr>
187<tr>
188 <ti>The Compaq Java Kit for Alpha/Linux/GNU</ti>
189 <ti>dev-java/compaq-jdk</ti>
190 <ti>dev-java/compaq-jre</ti>
191</tr>
192<tr>
193 <ti>BEA WebLogic's J2SE Development Kit</ti>
194 <ti>dev-java/jrockit-jdk-bin</ti>
195</tr>
196</table>
197
198<!--
199TODO: list free implementations?
200note about not drop-in replacements
201kaffe/sablevm/gcj/jamvm
202-->
203<p>
204The default for Java 1.4 is the Blackdown JRE/JDK pair, as it is freely
205("free as in beer") available without any registration fuss.
206</p>
207
208<p>
209JREs and JDKs from Sun, IBM, and BEA are generally faster, but getting them
210is a bit more work, as you are required to read and accept their license before
211downloading (IBM additionally requires you to register).
212</p>
213
214</body>
215</section>
216<section>
217<title>Installing a JRE/JDKs</title>
218<body>
219
220<p>
221To install your profile's default JDK, you can run <c>emerge virtual/jdk</c>.
222Or to install your profile's default JRE, you can <c>emerge virtual/jre</c>.
223</p>
224
225<p>
226In recent events, Sun has relicensed their JDK and JRE under a more Linux
227distro friendly license. As a result, Sun releases Java 1.5 and onwards are
228freely downloadable, without any further hassle.
229</p>
230
231<note>
232A JDK also includes a JRE, so if you install a JDK you shouldn't have to also
233have to install a JRE.
50JDK.</note> 234</note>
51 235
236</body>
237</section>
238<section>
239<title>Installing fetch-restricted virtual machines</title>
240<body>
241
242<p>
243As already mentioned, some of the JDKs and JREs require you to jump through a
244few hoops before installing. Simply emerge the packages as you normally would.
245The ebuilds will then instruct you where to go and what to download.
246</p>
247
248<p>
52<p>You should download the indicated file(s) into 249You should download the indicated file(s) into
53<path>/usr/portage/distfiles</path>. Once that is done, you can rerun 250<path>/usr/portage/distfiles</path>. Once there, you can rerun the emerge
54the emerge command, then the JDK/JRE will be installed properly into 251command, at which point the JRE/JDK will be begin to install.
55<path>/opt</path>.</p> 252</p>
56</body>
57</section>
58</chapter>
59 253
254</body>
255</section>
60<chapter> 256</chapter>
61<title>Configuring your JDK/JRE</title> 257
258<chapter>
259<title>Configuring your virtual machine</title>
62<section> 260<section>
63<title>Overview</title> 261<title>Overview</title>
64<body> 262<body>
263
264<p>
65<p>Gentoo has the ability to have multiple JDKs and JREs installed 265Gentoo has the ability to have multiple JDKs and JREs installed without causing
66without them conflicting. There are a few caveats to this, as noted 266conflicts.
67below.</p> 267</p>
68 268
269<p>
69<p>Using the <c>java-config</c> tool, you can set the system-wide 270Using the <c>java-config</c> tool, you can set the system-wide default
70default if you have root access. Users can also use <c>java-config</c> 271(provided you have root access). Users can also use <c>java-config</c> to set
71to set up their own personal default, that is different from the 272up their own personal default.
72system-wide default.</p> 273</p>
73</body>
74</section>
75 274
275<note>
276You can also use <e>eselect</e> to change the system and user vm. See
277<c>eselect java-vm help</c>.
278</note>
279
280</body>
76<section> 281</section>
282<section>
77<title>Setting a default JDK/JRE</title> 283<title>Setting a default virtual machine</title>
78<body> 284<body>
285
286<p>
79<p>Running the command <c>java-config --list-available-vms</c> will 287Running the command <c>java-config --list-available-vms</c> will give you a
80give you a list of all availble JREs and JDKs on your system, thus:</p> 288list of all JREs and JDKs installed on your system. Here is an example of
289output:
290</p>
291
292<pre caption="Listing available VMs">
293# <i>java-config --list-available-vms</i>
294The following VMs are available for generation-2:
2951) Blackdown JDK 1.4.2.03 [blackdown-jdk-1.4.2]
2962) Blackdown JRE 1.4.2.03 [blackdown-jre-1.4.2]
2973) Blackdown 32bit JRE 1.4.2.03 [emul-linux-x86-java-1.4.2]
2984) Sun 32bit JRE 1.5.0.08 [emul-linux-x86-java-1.5]
2995) Kaffe 1.1.7 [kaffe]
300*) Sun JDK 1.5.0.08 [sun-jdk-1.5]
81<pre> 301</pre>
82[%1 ~] java-config --list-available-vms 302
83[blackdown-jdk-1.3.1] Blackdown JDK 1.3.1 (/etc/env.d/java/20blackdown-jdk-1.3.1) 303<p>
84[blackdown-jre-1.3.1] Blackdown JRE 1.3.1 (/etc/env.d/java/20blackdown-jre-1.3.1) 304The <e>*</e> indicates this is the current active vm (system-vm or user-vm when
85[ibm-jdk-1.3.0] IBM JDK 1.3.0 (/etc/env.d/java/20ibm-jdk-1.3.0)
86[ibm-jdk-1.3.1] IBM JDK 1.3.1 (/etc/env.d/java/20ibm-jdk-1.3.1)
87[ibm-jre-1.3.1] IBM JRE 1.3.1 (/etc/env.d/java/20ibm-jre-1.3.1)
88[sun-jdk-1.4.0] Sun JDK 1.4.0 (/etc/env.d/java/20sun-jdk-1.4.0)
89</pre>
90<p>The name in the brackets <path>"[]"</path> is the handle or ID for 305set). The name in the brackets (<e>[]</e>) is the handle or ID for that
91that particular VM. You use pass that ID to <c>java-config 306particular VM. You use the handle or the number to <c>java-config
92--set-system-vm</c>, thus:</p> 307--set-system-vm</c>. Here is an example of how to set the system VM.
308</p>
309
310<pre caption="Setting the System VM">
311<comment>(By handle (preferred))</comment>
312# <i>java-config --set-system-vm blackdown-jdk-1.4</i>
313Now using blackdown-jdk-1.4 as your generation-2 system JVM
314<comment>(By number)</comment>
315# <i>java-config --set-system-vm 6</i>
316Now using sun-jdk-1.5 as your generation-2 system JVM
93<pre> 317</pre>
94[#1 ~] java-config --set-system-vm=ibm-jdk-1.3.1
95Now using IBM JDK 1.3.1 (/etc/env.d/java/20ibm-jdk-1.3.1)
96</pre>
97 318
98<note>You will have to be root to run --set-system-vm</note>
99
100<p>Once you have issued <c>java-config --set-system-vm</c> with a
101particular VM ID, you will need to regenerate your /etc/profile.env,
102thus:</p>
103<pre> 319<p>
104[#1 ~] env-update
105</pre>
106
107<p>After this, you will either want to relogin, or resource
108<path>/etc/profile</path> into your environment.</p>
109
110<p>As a regular user, you can use <c>java-config --set-user-vm</c>, 320As a regular user, you can use <c>java-config --set-user-vm</c>.
111which will create <path>$HOME/.gentoo/java-env</path> with all 321</p>
112required env vars. You would normally source this from your shell's
113startup script (<path>$HOME/.zshenv</path> in my case).</p>
114</body>
115</section>
116 322
323<note>
324You no longer have to <c>source</c> the profile for updates to the user/system
325VM take place.
326</note>
327
328</body>
117<section> 329</section>
330<section id="preferred-vm">
331<title>Preferred VM</title>
332<body>
333
334<p>
335While merging Java packages, the VM can and will be switched as necessary.
336</p>
337
338<p>
339Because of the wide variety of available VMs, we do not have the resources to
340test and verify every package works on all of them. So to ensure that every
341packages merges smoothly, we have defined a list of <e>default/supported
342VMs</e> per arch. You can find them in
343<path>/usr/share/java-config/config/jdk-defaults.conf</path>. When you are
344merging a Java package, and it detects one of the VM in that file is installed,
345it will automatically use that VM, instead of the system-vm.
346</p>
347
348<p>
349The merge time VM switching is also needed when, for example, your system-vm is
350set a 1.4 VM and the package you are merging requires a 1.5 VM. While merging
351it will use the preferred 1.5 VM, leaving your system-vm choice intact.
352</p>
353
354<p>
355Of course, Gentoo is all about choice, so you can override these defaults in
356<path>/etc/java-config-2/build/jdk.conf</path> and have complete control over
357which VM will get used. Some examples:
358</p>
359
360<pre caption="Example /etc/java-config-2/build/jdk.conf">
361<comment>(I always want it to use a sun-jdk, ie sun-jdk-1.4 for 1.4, sun-jdk-1.5 for 1.5, etc)</comment>
362*=sun-jdk
363</pre>
364
365<pre caption="Example /etc/java-config-2/build/jdk.conf">
366<comment>(Always use sun-jdk-1.5 wherever possible, except for when a 1.4 or 1.3 VM is explicitly required)</comment>
367*=sun-jdk-1.5
368</pre>
369
370<pre caption="Example /etc/java-config-2/build/jdk.conf">
371<comment># For 1.3 I prefer sun-jdk 1.4 but when it is not available, use ibm-jdk-bin,
372# For 1.4, use blackdown-jdk, and for 1.5, use sun-jdk </comment>
3731.3=sun-jdk-1.4 ibm-jdk-bin
3741.4=blackdown-jdk
3751.5=sun-jdk
376</pre>
377
378<warn>
379You do not have to edit this file. If you change these options to use a
380unsupported VM, things could possibly break. Bugs reported with a unsupported
381VM won't be prioritized as much as bugs present within supported VMs.
382</warn>
383
384</body>
385</section>
386</chapter>
387
388<chapter>
389<title>Compilers</title>
390<section>
391<body>
392
393<p>
394The standard Java compiler used for building is javac, which comes with each
395JDK. In addition to configuring the VM used at build time, it is also possible
396configure which compiler is used. Essentially, you define a list your
397preference for which compiler to use in
398<path>/etc/java-config-2/build/compilers.conf</path>.
399</p>
400
401<pre caption="/etc/java-config-2/build/compilers.conf">
402# If the ebuild supports it
403# it will check the COMPILERS var front to back and
404# use the first compiler that is installed
405
406COMPILERS="ecj-3.1 jikes javac"
407</pre>
408
409<p>
410Some compilers don't support all possible -target and -source arguments.
411Therefore, each compiler in the list is checked to see if it can support the
412desired -source/-target. javac will work in all cases, so if no other suitable
413compiler is found, it will be used instead.
414</p>
415
416<p>
417More details about each compiler are provided below:
418</p>
419
420<table>
421<tr>
422 <th>Name</th>
423 <th>Handle</th>
424 <th>Package</th>
425 <th>Description</th>
426</tr>
427<tr>
428 <ti>javac</ti>
429 <ti>javac</ti>
430 <ti>N/A</ti>
431 <ti>
432 This is the default compiler that will be used, and comes with each JDK.
433 </ti>
434</tr>
435<tr>
436 <ti>jikes</ti>
437 <ti>jikes</ti>
438 <ti>dev-java/jikes</ti>
439 <ti>
440 Jikes was originally developed by IBM. Anecdotally, it is generally quicker
441 than javac. Note however, that it is more pedantic, and will fail under a
442 few circumstances where javac has no issue. It also does not support Java
443 1.5 syntax yet.
444 </ti>
445</tr>
446<tr>
447 <ti>Eclipse Compiler for Java</ti>
448 <ti>ecj-3.1</ti>
449 <ti>=dev-java/eclipse-ecj-3.1*</ti>
450 <ti>
451 ECJ is the compiler used by the Eclipse software development kit. It is
452 very full featured, and is pretty fast. It does support Java 1.5 syntax.
453 </ti>
454</tr>
455</table>
456
457</body>
458</section>
459</chapter>
460
461<chapter>
118<title>Setting a default CLASSPATH</title> 462<title>Setting a default CLASSPATH</title>
463<section>
119<body> 464<body>
465
466<warn>
467The options explained in this section should be considered deprecated and will
468most likely be removed in the future. We strongly recommend against using
469these, because your Java projects or application should ideally manage their
470own classpaths. If you choose to specify a default CLASSPATH, some applications
471may behave unexpectedly, because classes they weren't expecting would be on the
472classpath.
473</warn>
474
475<p>
120<p><c>java-config</c> can also be used to set a system-wide default 476<c>java-config</c> can also be used to set a system-wide default CLASSPATH, as
121CLASSPATH, and of course a user-specific default CLASSPATH.</p> 477well a user-specific default CLASSPATH.
478</p>
122 479
123<p>First you want to list available java libraries that might be 480<p>
124interesting to put in your CLASSPATH, thus:</p> 481First, you will want to list available Java libraries installed on your system
482that might want to be put in your CLASSPATH. Here is an example of output:
483</p>
484
485<pre caption="Listing classes">
486# <i>java-config --list-available-packages</i>
487[xerces-2] The next generation of high performance, fully compliant XML parsers in the Apache Xerces family (/usr/share/xerces-2/package.env)
488[junit] Simple framework to write repeatable tests (/usr/share/junit/package.env)
489[bsh] BeanShell: A small embeddable Java source interpreter (/usr/share/bsh/package.env)
490[bcel] The Byte Code Engineering Library: analyze, create, manipulate Java class files (/usr/share/bcel/package.env)
491[log4j] A low-overhead robust logging package for Java (/usr/share/log4j/package.env)
492...
125<pre> 493</pre>
126[%1 ~] java-config --list-available-packages 494
127[ant] No description (/usr/share/ant/classpath.env) 495<p>
128[java-gnome] No description (/usr/share/java-gnome/classpath.env) 496Again, the names in brackets (<e>[]</e>) are the IDs that you have to pass to
129[java-gtk] No description (/usr/share/java-gtk/classpath.env) 497<c>java-config --set-system-classpath</c>. Here is an example:
130[log4j] "" (/usr/share/log4j/package.env)
131</pre> 498</p>
132 499
133<note>None of these packages have a proper description. That is 500<pre caption="Setting classpaths">
134something that will be implemented in the not-so-distant 501# <i>java-config --set-system-classpath log4j,xerces-2</i>
135future.</note>
136
137<p>Again, the name in brackets <path>"[]"</path> are the IDs that you
138have to pass to <c>java-config --set-system-classpath</c>, thus:</p>
139<pre> 502</pre>
140java-config --set-system-classpath=log4j,java-gtk,java-gnome 503
504<note>
505The current directory (<path>.</path>) will not be part of the system
506classpath, as that should be added in your system's login profile.
507</note>
508
509<p>
510You will have to update your environment by logging out, then in again or
511sourcing <path>/etc/profile</path>.
141</pre> 512</p>
142<note>The current directory (.) will not be part of the system classpath, 513
143as that should be added in root's login profile.</note> 514<p>
144<p>Again, you will want to run <c>env-update</c> to update your
145system's environment, and you might also want to relogin or resource
146the <path>/etc/profile</path>.</p>
147<p>For users, <c>java-config --set-user-classpath</c> will create 515For users, <c>java-config --set-user-classpath</c> will create
148<path>$HOME/.gentoo/java-env-classpath</path>, which is automatically 516<path>~/.gentoo/java-env-classpath</path>, which you should then source from
149included by <path>$HOME/.gentoo/java-env</path>.</p> 517your shell's profile.
518</p>
519
520<pre caption="Sourcing user specific classpath">
521<i>if [[ -f "${HOME}/.gentoo/java-env-classpath" ]]; then
522 source ${HOME}/.gentoo/java-env-classpath
523fi</i>
524</pre>
525
526<p>
527If you really want a system wide or user default classpath you can add
528something like the following to your shell's profile. But we would advise
529against it.
530</p>
531
532<pre caption="Setting classpath">
533# <i>export CLASSPATH="${CLASSPATH}:$(java-config --classpath log4j,xerces-2)"</i>
534</pre>
535
536</body>
537</section>
538</chapter>
539
540<chapter>
541<title>Java Browser Plug-ins</title>
542<section>
543<title>Installing a plug-in</title>
544<body>
545
546<p>
547You can install a Java plug-in for your web browser by emerging a Java VM with
548the <c>nsplugin</c> USE flag set.
549</p>
550
551<note>
552<c>nsplugin</c> is not available for all architectures. Check for available
553plug-ins on your arch before trying to install a VM by running <c>emerge -pv
554&lt;java-vm&gt;</c>.
555</note>
556
557<p>
558Portage will allow you to install multiple versions of Java plug-ins, though
559only one will be used by your browser. You can check the list of available
560plug-ins by running:
561</p>
562
563<pre caption="Viewing available plug-ins">
564# <i>eselect java-nsplugin list</i>
565 [1] sun-jre-bin-1.5
566 [2] blackdown-jre-1.4.2
567</pre>
568
569<p>
570In this example, <c>sun-jre-bin</c> is selected for the browser plug-in.
571</p>
572
573<pre caption="Selecting a plug-in">
574# <i>eselect java-nsplugin sun-jre-bin-1.5</i>
575</pre>
576
577<p>
578Verify that the correct plug-in was selected:
579</p>
580
581<pre caption="Verifying the correct plug-in">
582# <i>eselect java-nsplugin list</i>
583 [1] sun-jre-bin-1.5 current
584 [2] blackdown-jre-1.4.2
585</pre>
586
587<p>
588Java.com also provides a link to <uri
589link="http://java.com/en/download/installed.jsp">verify your installed
590plug-in</uri>. Additionally, if you are using a Mozilla-based browser, you can
591verify your Java plug-in by typing <c>about:plugins</c> into the address bar.
592</p>
593
594</body>
595</section>
596<section>
597<title>Plug-ins on multilib systems</title>
598<body>
599
600<p>
601If you are running a mixed 64-bit and 32-bit multilib system (for example, on AMD64),
602you can have both 64-bit and a 32-bit Java plug-ins installed.
603</p>
604
605<p>
606First, check which plug-ins are available:
607</p>
608
609<pre caption="Viewing available plug-ins">
610# <i>eselect java-nsplugin list</i>
611Available 32-bit Java browser plugins
612 [1] emul-linux-x86-java-1.4.2
613 [2] emul-linux-x86-java-1.5
614Available 64-bit Java browser plugins
615 [1] blackdown-jdk-1.4.2
616 [2] blackdown-jre-1.4.2
617</pre>
618
619<p>
620You can select a 32-bit plug-in for a 32-bit browser (for example,
621<c>firefox-bin</c>), and you can select a 64-bit plug-in for your 64-bit
622browser (for example, <c>konqueror</c>).
623</p>
624
625<pre caption="Selecting plug-ins">
626# <i>eselect java-nsplugin set 32bit emul-linux-x86-java-1.4.2</i>
627# <i>eselect java-nsplugin set 64bit blackdown-jdk-1.4.2</i>
628</pre>
629
630<p>
631Verify the correct plug-ins were selected:
632</p>
633
634<pre caption="Verifying the correct plug-ins">
635# <i>eselect java-nsplugin list</i>
636Available 32-bit Java browser plugins
637 [1] emul-linux-x86-java-1.4.2 current
638 [2] emul-linux-x86-java-1.5
639Available 64-bit Java browser plugins
640 [1] blackdown-jdk-1.4.2 current
641 [2] blackdown-jre-1.4.2
642</pre>
643
644</body>
645</section>
646</chapter>
647
648<chapter>
649<title>USE flags for use with Java</title>
650<section>
651<title>Setting USE flags</title>
652<body>
653
654<p>
655For more information regarding USE flags, refer to the <uri
656link="/doc/en/handbook/handbook-x86.xml?part=2&amp;chap=2">USE flags</uri>
657chapter from the Gentoo Handbook.
658</p>
659
660</body>
661</section>
662<section>
663<title>The flags</title>
664<body>
665
666<ul>
667 <li>The <b>java</b> flag adds support for Java in a variety of programs</li>
668 <li>
669 The <b>nsplugin</b> flag adds support for Mozilla-like browsers (including
670 Firefox). You will need this for viewing Java applets in your Mozilla-like
671 browser.
672 </li>
673 <li>
674 The <b>source</b> flag installs a zip of the source code of a package.
675 This is traditionally used for IDEs to 'attach' source to the libraries you
676 are using.
677 </li>
678 <li>
679 For Java packages, the <b>doc</b> flag will build API documentation using
680 javadoc.
681 </li>
682</ul>
683
150</body> 684</body>
151</section> 685</section>
152</chapter> 686</chapter>
153 687
154<chapter> 688<chapter>
155<title>Additional resources</title> 689<title>Additional resources</title>
156<section> 690<section>
157<title>Off-line resources</title> 691<title>Off-line resources</title>
158<body> 692<body>
693
159<ul> 694<ul>
160<li>java-config man page</li> 695 <li>java-config man page</li>
161<li><c>java-config --help</c></li> 696 <li><c>java-config --help</c></li>
162<li>The <path>/usr/bin/java-config</path> script itself</li>
163</ul> 697</ul>
698
164</body> 699</body>
165</section> 700</section>
166<section> 701<section>
167<title>Online resources</title> 702<title>Online resources</title>
168<body> 703<body>
704
169<ul> 705<ul>
170<li>The <uri link="http://lists.gentoo.org/pipermail/gentoo-dev/"> 706 <li>
171gentoo-dev </uri>, 707 The <uri link="http://www.gentoo.org/proj/en/java/">Java Project
172<uri link="http://lists.gentoo.org/pipermail/gentoo-user/"> gentoo-user 708 Page</uri>
709 </li>
710 <li>
711 The <uri
712 link="http://news.gmane.org/gmane.linux.gentoo.java">gentoo-java</uri>,
713 <uri
714 link="http://news.gmane.org/gmane.linux.gentoo.user">gentoo-user</uri>, and
715 <uri
716 link="http://news.gmane.org/gmane.linux.gentoo.devel">gentoo-dev</uri>
173</uri> mailing list archives</li> 717 mailing list archives
174<li>#gentoo on irc.openprojects.net</li> 718 </li>
719 <li>#gentoo and #gentoo-java on irc.freenode.net</li>
720 <li>
721 <uri
722 link="http://en.wikipedia.org/wiki/Java_programming_language">Wikipedia's
723 entry for Java</uri>
724 </li>
175</ul> 725</ul>
176</body>
177</section>
178</chapter>
179<chapter>
180<title>Caveats</title>
181<section>
182<title>General</title>
183<body>
184<p>If you select a JRE as your default VM, you may not have a
185<c>javac</c> command handy at all times, unless you have manually
186installed a symlink to take care of that.</p>
187 726
188<p>Jikes will be used to compile some of the largest packages, if it
189is available. With time, we hope to be able to compile all
190java-dependent packages with Jikes, so some dependencies on the JDK
191can be replaced with a dependency on the JRE.</p>
192
193<p>With some versions of Portage, doing an <c>emerge --world
194update</c> will install the JDK regardless if whether you have it
195installed before or not. This is a known bug addressed in later
196versions of Portage.</p>
197</body> 727</body>
198</section> 728</section>
199</chapter> 729</chapter>
200</guide> 730</guide>

Legend:
Removed from v.1.1  
changed lines
  Added in v.1.34

  ViewVC Help
Powered by ViewVC 1.1.20