1 <!doctype html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2 <html> 3 <head> 4 <meta http-equiv="content-type" content="text/html; charset=iso-8859-1"> 5 <meta http-equiv="content-style-type" content="text/css"> 6 <link rel="stylesheet" type="text/css" href="style.css"> 7 <title>ProGuard Limitations</title> 8 <script type="text/javascript" language="JavaScript"> 9 <!-- 10 if (window.self==window.top) 11 window.top.location.replace("../index.html#"+window.location.pathname+window.location.hash); 12 else { 13 var hash="#"+window.location.pathname.replace(window.top.location.pathname.replace("index.html", ""), ""); 14 if (window.top.location.hash!=hash) 15 window.top.location.hash=hash; 16 } 17 //--> 18 </script> 19 </head> 20 <body> 21 22 <h2>Limitations</h2> 23 24 When using ProGuard, you should be aware of a few technical issues, all of 25 which are easily avoided or resolved: 26 <p> 27 <ul class="spacious"> 28 29 <li>For best results, ProGuard's optimization algorithms assume that the 30 processed code never <b>intentionally throws NullPointerExceptions</b> or 31 ArrayIndexOutOfBoundsExceptions, or even OutOfMemoryErrors or 32 StackOverflowErrors, in order to achieve something useful. For instance, 33 it may remove a method call <code>myObject.myMethod()</code> if that call 34 wouldn't have any effect. It ignores the possibility that 35 <code>myObject</code> might be null, causing a NullPointerException. In 36 some way this is a good thing: optimized code may throw fewer exceptions. 37 Should this entire assumption be false, you'll have to switch off 38 optimization using the <code>-dontoptimize</code> option.</li> 39 40 <li>ProGuard's optimization algorithms currently also assume that the 41 processed code never creates <b>busy-waiting loops</b> without at least 42 testing on a volatile field. Again, it may remove such loops. Should this 43 assumption be false, you'll have to switch off optimization using 44 the <code>-dontoptimize</code> option.</li> 45 46 <li>If an input jar and a library jar contain classes in the <b>same 47 package</b>, the obfuscated output jar may contain class names that 48 overlap with class names in the library jar. This is most likely if the 49 library jar has been obfuscated before, as it will then probably contain 50 classes named 'a', 'b', etc. Packages should therefore never be split 51 across input jars and library jars.</li> 52 53 <li>When obfuscating, ProGuard writes out class files named 54 "<code>a.class</code>", "<code>b.class</code>", etc. If a package contains 55 a large number of classes, ProGuard may also write out 56 <b>"<code>aux.class</code>"</b>. Inconveniently, Windows refuses to create 57 files with this reserved name (among a few other names). It's generally 58 better to write the output to a jar, in order to avoid such problems.</li> 59 60 </ul> 61 62 <hr /> 63 <noscript><div><a target="_top" href="../index.html" class="button">Show menu</a></div></noscript> 64 <address> 65 Copyright © 2002-2011 66 <a target="other" href="http://www.lafortune.eu/">Eric Lafortune</a>. 67 </address> 68 </body> 69 </html> 70
