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 </head> 9 <body> 10 11 <script type="text/javascript" language="JavaScript"> 12 <!-- 13 if (window.self==window.top) 14 document.write('<a class="largebutton" target="_top" href="../index.html#manual/limitations.html">ProGuard index</a> <a class="largebutton" target="_top" href="http://www.saikoa.com/dexguard">DexGuard</a> <a class="largebutton" target="_top" href="http://www.saikoa.com/">Saikoa</a> <a class="largebutton" target="other" href="http://sourceforge.net/projects/proguard/">Sourceforge</a>') 15 //--> 16 </script> 17 <noscript> 18 <a class="largebutton" target="_top" href="../index.html#manual/limitations.html">ProGuard index</a> 19 <a class="largebutton" target="_top" href="http://www.saikoa.com/dexguard">DexGuard</a> 20 <a class="largebutton" target="_top" href="http://www.saikoa.com/">Saikoa</a> 21 <a class="largebutton" target="other" href="http://sourceforge.net/projects/proguard/">Sourceforge</a> 22 </noscript> 23 24 <h2>Limitations</h2> 25 26 When using ProGuard, you should be aware of a few technical issues, all of 27 which are easily avoided or resolved: 28 <p> 29 <ul class="spacious"> 30 31 <li>For best results, ProGuard's optimization algorithms assume that the 32 processed code never <b>intentionally throws NullPointerExceptions</b> or 33 ArrayIndexOutOfBoundsExceptions, or even OutOfMemoryErrors or 34 StackOverflowErrors, in order to achieve something useful. For instance, 35 it may remove a method call <code>myObject.myMethod()</code> if that call 36 wouldn't have any effect. It ignores the possibility that 37 <code>myObject</code> might be null, causing a NullPointerException. In 38 some way this is a good thing: optimized code may throw fewer exceptions. 39 Should this entire assumption be false, you'll have to switch off 40 optimization using the <code>-dontoptimize</code> option.</li> 41 42 <li>ProGuard's optimization algorithms currently also assume that the 43 processed code never creates <b>busy-waiting loops</b> without at least 44 testing on a volatile field. Again, it may remove such loops. Should this 45 assumption be false, you'll have to switch off optimization using 46 the <code>-dontoptimize</code> option.</li> 47 48 <li>If an input jar and a library jar contain classes in the <b>same 49 package</b>, the obfuscated output jar may contain class names that 50 overlap with class names in the library jar. This is most likely if the 51 library jar has been obfuscated before, as it will then probably contain 52 classes named 'a', 'b', etc. Packages should therefore never be split 53 across input jars and library jars.</li> 54 55 <li>When obfuscating, ProGuard writes out class files named 56 "<code>a.class</code>", "<code>b.class</code>", etc. If a package contains 57 a large number of classes, ProGuard may also write out 58 <b>"<code>aux.class</code>"</b>. Inconveniently, Windows refuses to create 59 files with this reserved name (among a few other names). It's generally 60 better to write the output to a jar, in order to avoid such problems.</li> 61 62 </ul> 63 64 <hr /> 65 <address> 66 Copyright © 2002-2014 67 <a target="other" href="http://www.lafortune.eu/">Eric Lafortune</a> @ <a target="top" href="http://www.saikoa.com/">Saikoa</a>. 68 </address> 69 </body> 70 </html> 71
