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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 1.28 2006/08/08 09:51:12 rane 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>0.6</version>
14<date>June 25, 2002</date> 28<date>2006-08-07</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, i.e. x86, ppc, or amd64 as opposed to ~x86,
79~ppc, or ~amd64, you will need to add some entries to your
80<path>/etc/portage/package.keywords</path>:
81</p>
82
83<pre caption="package.keywords">
84# Core Gentoo/Java Packages
85dev-java/ant-core
86dev-java/ant-tasks
87dev-java/ant
88dev-java/java-config
89dev-java/java-config-wrapper
90dev-java/javatoolkit
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<impo>
123It is crucial that you keyword ALL packages related to the new Java system,
124otherwise you will have problems in the later steps of this guide.
125</impo>
126
127<impo>
128It can't be emphasized enough that you have to have ALL the packages related
129to the new Java system keyworded for it to function properly.
130</impo>
131
132</body>
133</section>
134<section>
135<title>Existing installs</title>
136<body>
137
138<p>
139For existing installs, regardless of if you have installed anything Java
140before, make sure you have followed the <uri
141link="/proj/en/java/java-upgrade.xml">Java Upgrade Guide</uri>.
142</p>
143
144</body>
145</section>
146<section>
147<title>New installs</title>
148<body>
149
150<p>
151New installs should require no further preparation.
152</p>
153
154</body>
155</section>
156</chapter>
157
158<chapter>
159<title>Installing a Virtual Machine</title>
160<section>
161<title>The choices</title>
162<body>
163
164<p>
165Gentoo provides numerous Runtime Environments (JREs) and Development Kits
166(JDKs). Among the current choices, we have:
167</p>
168
169<table>
170<tr>
171 <th>Vendor</th>
172 <th>JDK</th>
173 <th>JRE</th>
174</tr>
175<tr>
176 <ti>The Blackdown Java Kit</ti>
177 <ti>dev-java/blackdown-jdk</ti>
178 <ti>dev-java/blackdown-jre</ti>
179</tr>
180<tr>
181 <ti>Sun's Java Kit</ti>
182 <ti>dev-java/sun-jdk</ti>
183 <ti>dev-java/sun-jre-bin</ti>
184</tr>
185<tr>
186 <ti>The IBM Java Kit</ti>
187 <ti>dev-java/ibm-jdk-bin</ti>
188 <ti>dev-java/ibm-jre-bin</ti>
189</tr>
190<tr>
191 <ti>The Compaq Java Kit for Alpha/Linux/GNU</ti>
192 <ti>dev-java/compaq-jdk</ti>
193 <ti>dev-java/compaq-jre</ti>
194</tr>
195<tr>
196 <ti>BEA WebLogic's J2SE Development Kit</ti>
197 <ti>dev-java/jrockit-jdk-bin</ti>
198</tr>
199</table>
200
201<!--
202TODO: list free implementations?
203note about not drop-in replacements
204kaffe/sablevm/gcj/jamvm
205-->
206
207<p>
208The default is Blackdown for both the JRE and the JDK, as it is freely ("free
209as in beer") available without any registration fuss.
210</p>
211
212<p>
213The default for Java 1.4 is the Blackdown JRE/JDK pair, as it is freely
214("free as in beer") available without any registration fuss.
215</p>
216
217<p>
218JREs and JDKs from Sun, IBM, and BEA are generally faster, but getting them
219is a bit more work, as you are required to read and accept their license before
220downloading (IBM additionally requires you to register).
221</p>
222
223</body>
224</section>
225<section>
226<title>Installing a JRE/JDKs</title>
227<body>
228
229<p>
230To install your profile's default JDK, you can run <c>emerge virtual/jdk</c>.
231Or to install your profile's default JRE, you can <c>emerge virtual/jre</c>.
232</p>
233
234<p>
235In recent events, Sun has relicensed their JDK and JRE under a more Linux
236distro friendly license. As a result, Sun releases Java 1.5 and onwards are
237freely downloadable, without any further hassle.
238</p>
239
240<note>
241A JDK also includes a JRE, so if you install a JDK you shouldn't have to also
242have to install a JRE.
50JDK.</note> 243</note>
51 244
245</body>
246</section>
247<section>
248<title>Installing fetch-restricted virtual machines</title>
249<body>
250
251<p>
252As already mentioned, some of the JDKs and JREs require you to jump through a
253few hoops before installing. Simply emerge the packages as you normally would.
254The ebuilds will then instruct you where to go and what to download.
255</p>
256
257<p>
52<p>You should download the indicated file(s) into 258You should download the indicated file(s) into
53<path>/usr/portage/distfiles</path>. Once that is done, you can rerun 259<path>/usr/portage/distfiles</path>. Once there, you can rerun the emerge
54the emerge command, then the JDK/JRE will be installed properly into 260command, at which point the JRE/JDK will be begin to install.
55<path>/opt</path>.</p> 261</p>
56</body>
57</section>
58</chapter>
59 262
263</body>
264</section>
60<chapter> 265</chapter>
61<title>Configuring your JDK/JRE</title> 266
267<chapter>
268<title>Configuring your virtual machine</title>
62<section> 269<section>
63<title>Overview</title> 270<title>Overview</title>
64<body> 271<body>
272
273<p>
65<p>Gentoo has the ability to have multiple JDKs and JREs installed 274Gentoo has the ability to have multiple JDKs and JREs installed without causing
66without them conflicting. There are a few caveats to this, as noted 275conflicts.
67below.</p> 276</p>
68 277
278<p>
69<p>Using the <c>java-config</c> tool, you can set the system-wide 279Using 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> 280(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 281up their own personal default.
72system-wide default.</p> 282</p>
73</body>
74</section>
75 283
284<note>
285You can also use <e>eselect</e> to change the system and user vm. See
286<c>eselect java-vm help</c>.
287</note>
288
289</body>
76<section> 290</section>
291<section>
77<title>Setting a default JDK/JRE</title> 292<title>Setting a default virtual machine</title>
78<body> 293<body>
294
295<p>
79<p>Running the command <c>java-config --list-available-vms</c> will 296Running 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> 297list of all JREs and JDKs installed on your system. Here is an example of
298output:
299</p>
300
301<pre caption="Listing available VMs">
302# <i>java-config --list-available-vms</i>
3031) Blackdown JDK 1.3.1 [blackdown-jdk-1.3] (/etc/env.d/java/20blackdown-jdk-1.3)
3042) Blackdown JDK 1.4.2.02 [blackdown-jdk-1.4] (/etc/env.d/java/20blackdown-jdk-1.4)
3053) Blackdown JRE 1.4.2.02 [blackdown-jre-1.4] (/etc/env.d/java/20blackdown-jre-1.4)
3064) IBM JDK 1.4.2 [ibm-jdk-bin-1.4] (/etc/env.d/java/20ibm-jdk-bin-1.4)
3075) IBM JRE 1.4.2 [ibm-jre-bin-1.4] (/etc/env.d/java/20ibm-jre-bin-1.4)
3086) WebLogic JRockit 1.4.2.05 [jrockit-jdk-bin-1.4] (/etc/env.d/java/20jrockit-jdk-bin-1.4)
3097) WebLogic JRockit 1.5.0.03 [jrockit-jdk-bin-1.5] (/etc/env.d/java/20jrockit-jdk-bin-1.5)
3108) Sun JDK 1.3.1.13 [sun-jdk-1.3] (/etc/env.d/java/20sun-jdk-1.3)
3119) Sun JDK 1.4.2.09 [sun-jdk-1.4] (/etc/env.d/java/20sun-jdk-1.4)
312*) Sun JDK 1.5.0.04 [sun-jdk-1.5] (/etc/env.d/java/20sun-jdk-1.5)
31311) Sun JRE 1.4.2.09 [sun-jre-bin-1.4] (/etc/env.d/java/20sun-jre-bin-1.4)
31412) Sun JRE 1.5.0.04 [sun-jre-bin-1.5] (/etc/env.d/java/20sun-jre-bin-1.5)
81<pre> 315</pre>
82[%1 ~] java-config --list-available-vms 316
83[blackdown-jdk-1.3.1] Blackdown JDK 1.3.1 (/etc/env.d/java/20blackdown-jdk-1.3.1) 317<p>
84[blackdown-jre-1.3.1] Blackdown JRE 1.3.1 (/etc/env.d/java/20blackdown-jre-1.3.1) 318The <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 319set). 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 320particular VM. You use the handle or the number to <c>java-config
92--set-system-vm</c>, thus:</p> 321--set-system-vm</c>. Here is an example of how to set the system VM.
322</p>
323
324<pre caption="Setting the System VM">
325<comment>(By handle (preferred))</comment>
326# <i>java-config --set-system-vm blackdown-jdk-1.4</i>
327<comment>(By number)</comment>
328# <i>java-config --set-system-vm 2</i>
93<pre> 329</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>
97 330
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> 331<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>, 332As a regular user, you can use <c>java-config --set-user-vm</c>.
111which will create <path>$HOME/.gentoo/java-env</path> with all 333</p>
112required env vars. You would normally source this from your shell's
113startup script (<path>$HOME/.zshenv</path> in my case).</p>
114</body>
115</section>
116 334
335<note>
336You no longer have to <c>source</c> the profile for updates to the user/system
337VM take place.
338</note>
339
340</body>
117<section> 341</section>
342<section id="preferred-vm">
343<title>Preferred VM</title>
344<body>
345
346<p>
347While merging Java packages, the VM can and will be switched as necessary.
348</p>
349
350<p>
351Because of the wide variety of available VMs, we do not have the resources to
352test and verify every package works on all of them. So to ensure that every
353packages merges smoothly, we have defined a list of <e>default/supported
354VMs</e> per arch. You can find them in
355<path>/usr/share/java-config/config/jdk-defaults.conf</path>. When you are
356merging a Java package, and it detects one of the VM in that file is installed,
357it will automatically use that VM, instead of the system-vm.
358</p>
359
360<p>
361The merge time VM switching is also needed when, for example, your system-vm is
362set a 1.4 VM and the package you are merging requires a 1.5 VM. While merging
363it will use the preferred 1.5 VM, leaving your system-vm choice intact.
364</p>
365
366<p>
367Of course, Gentoo is all about choice, so you can override these defaults in
368<path>/etc/java-config-2/build/jdk.conf</path> and have complete control over
369which VM will get used. Some examples:
370</p>
371
372<pre caption="Example /etc/java-config-2/build/jdk.conf">
373<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>
374*=sun-jdk
375</pre>
376
377<pre caption="Example /etc/java-config-2/build/jdk.conf">
378<comment>(Always use sun-jdk-1.5 wherever possible, except for when a 1.4 or 1.3 VM is explicitly required)</comment>
379*=sun-jdk-1.5
380</pre>
381
382<pre caption="Example /etc/java-config-2/build/jdk.conf">
383<comment># For 1.3 I prefer sun-jdk 1.4 but when it is not available, use ibm-jdk-bin,
384# For 1.4, use blackdown-jdk, and for 1.5, use sun-jdk </comment>
3851.3=sun-jdk-1.4 ibm-jdk-bin
3861.4=blackdown-jdk
3871.5=sun-jdk
388</pre>
389
390<warn>
391You do not have to edit this file. If you change these options to use a
392unsupported VM, things could possibly break. Bugs reported with a unsupported
393VM won't be prioritized as much as bugs present within supported VMs.
394</warn>
395
396</body>
397</section>
398</chapter>
399
400<chapter>
401<title>Compilers</title>
402<section>
403<body>
404
405<p>
406The standard Java compiler used for building is javac, which comes with each
407JDK. In addition to configuring the VM used at build time, it is also possible
408configure which compiler is used. Essentially, you define a list your
409preference for which compiler to use in
410<path>/etc/java-config-2/build/compilers.conf</path>.
411</p>
412
413<pre caption="/etc/java-config-2/build/compilers.conf">
414# If the ebuild supports it
415# it will check the COMPILERS var front to back and
416# use the first compiler that is installed
417
418COMPILERS="ecj-3.1 jikes javac"
419</pre>
420
421<p>
422Some compilers don't support all possible -target and -source arguments.
423Therefore, each compiler in the list is checked to see if it can support the
424desired -source/-target. javac will work in all cases, so if no other suitable
425compiler is found, it will be used instead.
426</p>
427
428<p>
429More details about each compiler are provided below:
430</p>
431
432<table>
433<tr>
434 <th>Name</th>
435 <th>Handle</th>
436 <th>Package</th>
437 <th>Description</th>
438</tr>
439<tr>
440 <ti>javac</ti>
441 <ti>javac</ti>
442 <ti>N/A</ti>
443 <ti>
444 This is the default compiler that will be used, and comes with each JDK.
445 </ti>
446</tr>
447<tr>
448 <ti>jikes</ti>
449 <ti>jikes</ti>
450 <ti>dev-java/jikes</ti>
451 <ti>
452 Jikes was originally developed by IBM. Anecdotally, it is generally quicker
453 than javac. Note however, that it is more pedantic, and will fail under a
454 few circumstances where javac has no issue. It also does not support Java
455 1.5 syntax yet.
456 </ti>
457</tr>
458<tr>
459 <ti>Eclipse Compiler for Java</ti>
460 <ti>ecj-3.1</ti>
461 <ti>=dev-java/eclipse-ecj-3.1*</ti>
462 <ti>
463 ECJ is the compiler used by the Eclipse software development kit. It is
464 very full featured, and is pretty fast. It does support Java 1.5 syntax.
465 </ti>
466</tr>
467</table>
468
469</body>
470</section>
471</chapter>
472
473<chapter>
118<title>Setting a default CLASSPATH</title> 474<title>Setting a default CLASSPATH</title>
475<section>
119<body> 476<body>
477
478<warn>
479The options explained in this section should be considered deprecated and will
480most likely be removed in the future. We strongly recommend against using
481these, because your Java projects or application should ideally manage their
482own classpaths. If you choose to specify a default CLASSPATH, some applications
483may behave unexpectedly, because classes they weren't expecting would be on the
484classpath.
485</warn>
486
487<p>
120<p><c>java-config</c> can also be used to set a system-wide default 488<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> 489well a user-specific default CLASSPATH.
490</p>
122 491
123<p>First you want to list available java libraries that might be 492<p>
124interesting to put in your CLASSPATH, thus:</p> 493First, you will want to list available Java libraries installed on your system
494that might want to be put in your CLASSPATH. Here is an example of output:
495</p>
496
497<pre caption="Listing classes">
498# <i>java-config --list-available-packages</i>
499[xerces-2] The next generation of high performance, fully compliant XML parsers in the Apache Xerces family (/usr/share/xerces-2/package.env)
500[junit] Simple framework to write repeatable tests (/usr/share/junit/package.env)
501[bsh] BeanShell: A small embeddable Java source interpreter (/usr/share/bsh/package.env)
502[bcel] The Byte Code Engineering Library: analyze, create, manipulate Java class files (/usr/share/bcel/package.env)
503[log4j] A low-overhead robust logging package for Java (/usr/share/log4j/package.env)
504...
125<pre> 505</pre>
126[%1 ~] java-config --list-available-packages 506
127[ant] No description (/usr/share/ant/classpath.env) 507<p>
128[java-gnome] No description (/usr/share/java-gnome/classpath.env) 508Again, 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) 509<c>java-config --set-system-classpath</c>. Here is an example:
130[log4j] "" (/usr/share/log4j/package.env)
131</pre> 510</p>
132 511
133<note>None of these packages have a proper description. That is 512<pre caption="Setting classpaths">
134something that will be implemented in the not-so-distant 513# <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> 514</pre>
140java-config --set-system-classpath=log4j,java-gtk,java-gnome 515
516<note>
517The current directory (<path>.</path>) will not be part of the system
518classpath, as that should be added in your system's login profile.
519</note>
520
521<p>
522You will have to update your environment by logging out, then in again or
523sourcing <path>/etc/profile</path>.
141</pre> 524</p>
142<note>The current directory (.) will not be part of the system classpath, 525
143as that should be added in root's login profile.</note> 526<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 527For users, <c>java-config --set-user-classpath</c> will create
148<path>$HOME/.gentoo/java-env-classpath</path>, which is automatically 528<path>~/.gentoo/java-env-classpath</path>, which you should then source from
149included by <path>$HOME/.gentoo/java-env</path>.</p> 529your shell's profile.
530</p>
531
532<pre caption="Sourcing user specific classpath">
533<i>if [[ -f "${HOME}/.gentoo/java-env-classpath" ]]; then
534 source ${HOME}/.gentoo/java-env-classpath
535fi</i>
536</pre>
537
538<p>
539If you really want a system wide or user default classpath you can add
540something like the following to your shell's profile. But we would advise
541against it.
542</p>
543
544<pre caption="Setting classpath">
545# <i>export CLASSPATH="${CLASSPATH}:$(java-config --classpath log4j,xerces-2)"</i>
546</pre>
547
548</body>
549</section>
550</chapter>
551
552<chapter>
553<title>USE flags for use with Java</title>
554<section>
555<title>Setting USE flags</title>
556<body>
557
558<p>
559For more information regarding USE flags, refer to the <uri
560link="/doc/en/handbook/handbook-x86.xml?part=2&amp;chap=2">USE flags</uri>
561chapter from the Gentoo Handbook.
562</p>
563
564</body>
565</section>
566<section>
567<title>The flags</title>
568<body>
569
570<ul>
571 <li>The <b>java</b> flag adds support for Java in a variety of programs</li>
572 <li>
573 The <b>nsplugin</b> flag adds support for Mozilla-like browsers (including
574 Firefox).You will need this for viewing Java applets in your Mozilla-like
575 browser.
576 </li>
577 <li>
578 The <b>doc</b> flag will typically install API documentation, as generated
579 by javadoc.
580 </li>
581 <li>
582 The <b>source</b> flag will install a zip of the package's source code.
583 This is typically used to provide your IDE with the source code for the
584 package.
585 </li>
586 <li>
587 The <b>source</b> flag installs a zip of the source code of a package.
588 This is traditionally used for for IDEs to 'attach' source to the libraries
589 you are using.
590 </li>
591 <li>
592 For Java packages, the <b>doc</b> flag will build API documentation using
593 javadoc.
594 </li>
595</ul>
596
150</body> 597</body>
151</section> 598</section>
152</chapter> 599</chapter>
153 600
154<chapter> 601<chapter>
155<title>Additional resources</title> 602<title>Additional resources</title>
156<section> 603<section>
157<title>Off-line resources</title> 604<title>Off-line resources</title>
158<body> 605<body>
606
159<ul> 607<ul>
160<li>java-config man page</li> 608 <li>java-config man page</li>
161<li><c>java-config --help</c></li> 609 <li><c>java-config --help</c></li>
162<li>The <path>/usr/bin/java-config</path> script itself</li>
163</ul> 610</ul>
611
164</body> 612</body>
165</section> 613</section>
166<section> 614<section>
167<title>Online resources</title> 615<title>Online resources</title>
168<body> 616<body>
617
169<ul> 618<ul>
170<li>The <uri link="http://lists.gentoo.org/pipermail/gentoo-dev/"> 619 <li>
171gentoo-dev </uri>, 620 The <uri link="http://www.gentoo.org/proj/en/java/">Java Project
172<uri link="http://lists.gentoo.org/pipermail/gentoo-user/"> gentoo-user 621 Page</uri>
622 </li>
623 <li>
624 The <uri
625 link="http://news.gmane.org/gmane.linux.gentoo.java">gentoo-java</uri>,
626 <uri
627 link="http://news.gmane.org/gmane.linux.gentoo.user">gentoo-user</uri>, and
628 <uri
629 link="http://news.gmane.org/gmane.linux.gentoo.devel">gentoo-dev</uri>
173</uri> mailing list archives</li> 630 mailing list archives
174<li>#gentoo on irc.openprojects.net</li> 631 </li>
632 <li>#gentoo and #gentoo-java on irc.freenode.net</li>
633 <li>
634 <uri
635 link="http://en.wikipedia.org/wiki/Java_programming_language">Wikipedia's
636 entry for Java</uri>
637 </li>
175</ul> 638</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>
187 639
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> 640</body>
198</section> 641</section>
199</chapter> 642</chapter>
200</guide> 643</guide>

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