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1<?xml version="1.0" encoding="UTF-8"?> 1<?xml version="1.0" encoding="UTF-8"?>
2<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/java.xml,v 1.44 2009/10/07 18:14:31 nightmorph Exp $ -->
3<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> 2<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/java.xml,v 1.51 2011/05/09 21:36:03 nightmorph Exp $ -->
4 4
5<guide link="/doc/en/java.xml"> 5<guide>
6<title>Gentoo Java Guide</title> 6<title>Gentoo Java Guide</title>
7 7
8<author title="Author"> 8<author title="Author">
9 <mail link="nichoj@gentoo.org">Joshua Nichols</mail> 9 <mail link="nichoj@gentoo.org">Joshua Nichols</mail>
10</author> 10</author>
22 22
23<!-- The content of this document is licensed under the CC-BY-SA license --> 23<!-- The content of this document is licensed under the CC-BY-SA license -->
24<!-- See http://creativecommons.org/licenses/by-sa/2.5 --> 24<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
25<license/> 25<license/>
26 26
27<version>0.19</version> 27<version>2</version>
28<date>2009-10-07</date> 28<date>2011-05-09</date>
29 29
30<chapter> 30<chapter>
31<title>What is Java?</title> 31<title>What is Java?</title>
32<section> 32<section>
33<title>Overview</title> 33<title>Overview</title>
55</body> 55</body>
56</section> 56</section>
57</chapter> 57</chapter>
58 58
59<chapter> 59<chapter>
60<title>Before You Begin</title>
61<section>
62<title>Existing installs</title>
63<body>
64
65<p>
66For existing installs, regardless of if you have installed anything Java
67before, make sure you have followed the <uri
68link="/proj/en/java/java-upgrade.xml">Java Upgrade Guide</uri>.
69</p>
70
71</body>
72</section>
73<section>
74<title>New installs</title>
75<body>
76
77<p>
78New installs should require no further preparation.
79</p>
80
81</body>
82</section>
83</chapter>
84
85<chapter>
86<title>Installing a Virtual Machine</title> 60<title>Installing a Virtual Machine</title>
87<section> 61<section>
88<title>The choices</title> 62<title>The choices</title>
89<body> 63<body>
90 64
98 <th>Vendor</th> 72 <th>Vendor</th>
99 <th>JDK</th> 73 <th>JDK</th>
100 <th>JRE</th> 74 <th>JRE</th>
101</tr> 75</tr>
102<tr> 76<tr>
103 <ti>The Blackdown Java Kit</ti>
104 <ti>dev-java/blackdown-jdk</ti>
105 <ti>dev-java/blackdown-jre</ti>
106</tr>
107<tr>
108 <ti>Sun's Java Kit</ti> 77 <ti>Sun's Java Kit</ti>
109 <ti>dev-java/sun-jdk</ti> 78 <ti>dev-java/sun-jdk</ti>
110 <ti>dev-java/sun-jre-bin</ti> 79 <ti>dev-java/sun-jre-bin</ti>
111</tr> 80</tr>
112<tr> 81<tr>
115 <ti>dev-java/ibm-jre-bin</ti> 84 <ti>dev-java/ibm-jre-bin</ti>
116</tr> 85</tr>
117<tr> 86<tr>
118 <ti>BEA WebLogic's J2SE Development Kit</ti> 87 <ti>BEA WebLogic's J2SE Development Kit</ti>
119 <ti>dev-java/jrockit-jdk-bin</ti> 88 <ti>dev-java/jrockit-jdk-bin</ti>
89</tr>
90<tr>
91 <ti>The IcedTea Open Java Kit</ti>
92 <ti>dev-java/icedtea6-bin</ti>
120</tr> 93</tr>
121</table> 94</table>
122 95
123<!-- 96<!--
124TODO: list free implementations? 97TODO: list free implementations?
125note about not drop-in replacements 98note about not drop-in replacements
126kaffe/sablevm/gcj/jamvm 99kaffe/sablevm/gcj/jamvm
127--> 100-->
128<p>
129The default for Java 1.6 is the Sun JRE/JDK pair.
130</p>
131
132</body> 101</body>
133</section> 102</section>
134<section> 103<section>
135<title>Installing a JRE/JDKs</title> 104<title>Installing a JRE/JDKs</title>
136<body> 105<body>
139To install your profile's default JDK, you can run <c>emerge virtual/jdk</c>. 108To install your profile's default JDK, you can run <c>emerge virtual/jdk</c>.
140Or to install your profile's default JRE, you can <c>emerge virtual/jre</c>. 109Or to install your profile's default JRE, you can <c>emerge virtual/jre</c>.
141</p> 110</p>
142 111
143<p> 112<p>
144In recent events, Sun has relicensed their JDK and JRE under a more Linux 113Some JDKs and JREs, including the Sun packages, require accepting an End User
145distro friendly license. As a result, Sun releases Java 1.5 and onwards are 114License Agreement, or EULA. If its license (such as dlj-1.1) is not listed in
146freely downloadable, without any further hassle. 115ACCEPT_LICENSE in <path>/etc/make.conf</path>, then you won't be able to install
116the JDK/JRE. For more information on how to add acceptable licenses to
117<path>make.conf</path>, please read the <uri
118link="/doc/en/handbook/handbook-x86.xml?part=2&amp;chap=1#doc_chap4">Portage
119Handbook</uri>.
120</p>
121
122<p>
123To avoid any restrictive license hassle, consider installing
124<c>icedtea6-bin</c>, which is an open Java implementation from the OpenJDK
125project.
147</p> 126</p>
148 127
149<note> 128<note>
150A JDK also includes a JRE, so if you install a JDK you shouldn't have to also 129A JDK also includes a JRE, so if you install a JDK you shouldn't have to also
151have to install a JRE. 130have to install a JRE.
208</p> 187</p>
209 188
210<pre caption="Listing available VMs"> 189<pre caption="Listing available VMs">
211# <i>java-config --list-available-vms</i> 190# <i>java-config --list-available-vms</i>
212The following VMs are available for generation-2: 191The following VMs are available for generation-2:
2131) Blackdown JDK 1.4.2.03 [blackdown-jdk-1.4.2] <comment>(Build Only)</comment>
2142) Blackdown JRE 1.4.2.03 [blackdown-jre-1.4.2] <comment>(Build Only)</comment>
2153) IcedTea6-bin 1.4.1 [icedtea6-bin] 1921) IcedTea6-bin 1.4.1 [icedtea6-bin]
2164) Sun JDK 1.5.0.20 [sun-jdk-1.5] <comment>(Build Only)</comment> 1932) Sun JDK 1.5.0.20 [sun-jdk-1.5] <comment>(Build Only)</comment>
217*) Sun JDK 1.6.0.16 [sun-jdk-1.6] 194*) Sun JDK 1.6.0.16 [sun-jdk-1.6]
218</pre> 195</pre>
219 196
220<note> 197<note>
221VMs marked as Build Only may contain security vulnerabilities and/or be EOL. 198VMs marked as Build Only may contain security vulnerabilities and/or be EOL.
231--set-system-vm</c>. Here is an example of how to set the system VM. 208--set-system-vm</c>. Here is an example of how to set the system VM.
232</p> 209</p>
233 210
234<pre caption="Setting the System VM"> 211<pre caption="Setting the System VM">
235<comment>(By handle (preferred))</comment> 212<comment>(By handle (preferred))</comment>
236# <i>java-config --set-system-vm blackdown-jdk-1.4</i> 213# <i>java-config --set-system-vm sun-jdk-1.6</i>
237Now using blackdown-jdk-1.4 as your generation-2 system JVM 214Now using sun-jdk-1.6 as your generation-2 system JVM
238WARNING: blackdown-jdk-1.4 is marked as a build-only JVM. Using this vm is not recommended.
239<comment>(By number)</comment> 215<comment>(By number)</comment>
240# <i>java-config --set-system-vm 5</i> 216# <i>java-config --set-system-vm 3</i>
241Now using sun-jdk-1.6 as your generation-2 system JVM 217Now using sun-jdk-1.6 as your generation-2 system JVM
242</pre> 218</pre>
243 219
244<p> 220<p>
245As a regular user, you can use <c>java-config --set-user-vm</c>. 221As a regular user, you can use <c>java-config --set-user-vm</c>.
269</p> 245</p>
270 246
271</body> 247</body>
272</section> 248</section>
273<section id="preferred-vm"> 249<section id="preferred-vm">
274<title>Preferred VM</title> 250<title>Preferred Build VM</title>
275<body> 251<body>
276 252
277<p>
278While merging Java packages, the VM can and will be switched as necessary.
279</p> 253<p>
280 254While merging Java packages, the VM used for building can sometimes be different
255from the one currently set as the system VM.
281<p> 256</p>
282Because of the wide variety of available VMs, we do not have the resources to 257
283test and verify every package works on all of them. So to ensure that every 258<p>
284packages merges smoothly, we have defined a list of <e>default/supported 259This merge time VM switching is needed when, for example, your system-vm is
260set to a 1.6 VM and the package you are merging requires a 1.5 VM. While merging
261it will select and use a 1.5 VM, leaving your system-vm choice intact.
262</p>
263
264<p>
265To define which VM is selected when a switch is needed, we have created a list of <e>default/supported
285VMs</e> per arch. You can find them in 266VMs</e> per arch. You can find them in
286<path>/usr/share/java-config-2/config/jdk-defaults.conf</path>. When you are 267<path>/usr/share/java-config-2/config/jdk-defaults.conf</path>.
287merging a Java package, and it detects one of the VM in that file is installed,
288it will automatically use that VM, instead of the system-vm.
289</p>
290
291<p> 268</p>
292The merge time VM switching is also needed when, for example, your system-vm is 269
293set a 1.4 VM and the package you are merging requires a 1.5 VM. While merging
294it will use the preferred 1.5 VM, leaving your system-vm choice intact.
295</p> 270<p>
296 271You can override these defaults (and even your selected system VM) in
297<p>
298Of course, Gentoo is all about choice, so you can override these defaults in
299<path>/etc/java-config-2/build/jdk.conf</path> and have complete control over 272<path>/etc/java-config-2/build/jdk.conf</path> and have complete control over
300which VM will get used. Some examples: 273which VM will get used for merging. Some examples:
301</p> 274</p>
302 275
303<pre caption="Example /etc/java-config-2/build/jdk.conf"> 276<pre caption="Example /etc/java-config-2/build/jdk.conf">
304<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> 277<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>
305*=sun-jdk 278*=sun-jdk
310*=sun-jdk-1.5 283*=sun-jdk-1.5
311</pre> 284</pre>
312 285
313<pre caption="Example /etc/java-config-2/build/jdk.conf"> 286<pre caption="Example /etc/java-config-2/build/jdk.conf">
314<comment># For 1.3 I prefer sun-jdk 1.4 but when it is not available, use ibm-jdk-bin, 287<comment># For 1.3 I prefer sun-jdk 1.4 but when it is not available, use ibm-jdk-bin,
315# For 1.4, use blackdown-jdk, and for 1.5, use sun-jdk </comment> 288# For 1.5, use sun-jdk </comment>
3161.3=sun-jdk-1.4 ibm-jdk-bin 2891.3=sun-jdk-1.4 ibm-jdk-bin
3171.4=blackdown-jdk
3181.5=sun-jdk 2901.5=sun-jdk
319</pre> 291</pre>
320 292
321<warn> 293<warn>
322You do not have to edit this file. If you change these options to use a 294You do not <e>have</e> to edit this file. If you change these options to use a
323unsupported VM, things could possibly break. Bugs reported with a unsupported 295unsupported VM, things could possibly break. Because of the wide variety of
296available VMs, we do not have the resources to test and verify every package
297works on all of them. Bugs reported with a unsupported VM won't be prioritized
324VM won't be prioritized as much as bugs present within supported VMs. 298as much as bugs present within supported VMs.
325</warn> 299</warn>
326 300
327</body> 301</body>
328</section> 302</section>
329</chapter> 303</chapter>
332<title>Compilers</title> 306<title>Compilers</title>
333<section> 307<section>
334<body> 308<body>
335 309
336<p> 310<p>
337The standard Java compiler used for building is javac, which comes with each 311The standard Java compiler used for building is <c>javac</c>, which comes with
338JDK. In addition to configuring the VM used at build time, it is also possible 312each JDK. In addition to configuring the VM used at build time, it is also
339configure which compiler is used. Essentially, you define a list your 313possible configure which compiler is used. Essentially, you define a list your
340preference for which compiler to use in 314preference for which compiler to use in
341<path>/etc/java-config-2/build/compilers.conf</path>. 315<path>/etc/java-config-2/build/compilers.conf</path>.
342</p> 316</p>
343 317
344<pre caption="/etc/java-config-2/build/compilers.conf"> 318<pre caption="/etc/java-config-2/build/compilers.conf">
345# If the ebuild supports it 319# If the ebuild supports it
346# it will check the COMPILERS var front to back and 320# it will check the COMPILERS var front to back and
347# use the first compiler that is installed 321# use the first compiler that is installed
348 322
349COMPILERS="ecj-3.1 jikes javac" 323COMPILERS="ecj-X.Y jikes javac"
350</pre> 324</pre>
351 325
352<p> 326<p>
353Some compilers don't support all possible -target and -source arguments. 327Some compilers don't support all possible -target and -source arguments.
354Therefore, each compiler in the list is checked to see if it can support the 328Therefore, each compiler in the list is checked to see if it can support the
386 1.5 syntax yet. 360 1.5 syntax yet.
387 </ti> 361 </ti>
388</tr> 362</tr>
389<tr> 363<tr>
390 <ti>Eclipse Compiler for Java</ti> 364 <ti>Eclipse Compiler for Java</ti>
391 <ti>ecj-3.1</ti> 365 <ti>ecj</ti>
392 <ti>=dev-java/eclipse-ecj-3.1*</ti> 366 <ti>dev-java/eclipse-ecj</ti>
393 <ti> 367 <ti>
394 ECJ is the compiler used by the Eclipse software development kit. It is 368 ECJ is the compiler used by the Eclipse software development kit. It is
395 very full featured, and is pretty fast. It does support Java 1.5 syntax. 369 very full featured, and is pretty fast. It does support Java 1.5 syntax.
396 </ti> 370 </ti>
397</tr> 371</tr>

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