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 <h2>Frequently Asked Questions</h2>

 <h3>Contents</h3>

 <ol>
 <li><a href="#shrinking">What is shrinking?</a></li>
 <li><a href="#obfuscation">What is obfuscation?</a></li>
 <li><a href="#preverification">What is preverification?</a></li>
 <li><a href="#optimization">What kind of optimizations does <b>ProGuard</b>
     support?</a></li>
 <li><a href="#commercial">Can I use <b>ProGuard</b> to process my commercial
     application?</a></li>
 <li><a href="#jdk1.4">Does <b>ProGuard</b> work with Java 2, 5, ..., 8?</a></li>
 <li><a href="#jme">Does <b>ProGuard</b> work with Java Micro Edition?</a></li>
 <li><a href="#android">Does <b>ProGuard</b> work for Android apps?</a></li>
 <li><a href="#blackberry">Does <b>ProGuard</b> work for Blackberry
     code?</a></li>
 <li><a href="#ant">Does <b>ProGuard</b> have support for Ant?</a></li>
 <li><a href="#gradle">Does <b>ProGuard</b> have support for Gradle?</a></li>
 <li><a href="#maven">Does <b>ProGuard</b> have support for Maven?</a></li>
 <li><a href="#gui">Does <b>ProGuard</b> come with a GUI?</a></li>
 <li><a href="#forname">Does <b>ProGuard</b> handle <code>Class.forName</code>
     calls?</a></li>
 <li><a href="#resource">Does <b>ProGuard</b> handle resource files?</a></li>
 <li><a href="#encrypt">Does <b>ProGuard</b> encrypt string constants?</a></li>
 <li><a href="#flow">Does <b>ProGuard</b> perform control flow
     obfuscation?</a></li>
 <li><a href="#incremental">Does <b>ProGuard</b> support incremental
     obfuscation?</a></li>
 <li><a href="#keywords">Can <b>ProGuard</b> obfuscate using reserved
     keywords?</a></li>
 <li><a href="#stacktrace">Can <b>ProGuard</b> reconstruct obfuscated stack
     traces?</a></li>
 <li><a href="#dexguard">How is <b>DexGuard</b> different from
     <b>ProGuard</b>?</a></li>
 </ol>

 <h3><a name="shrinking">What is shrinking?</a></h3>

 Java source code (.java files) is typically compiled to bytecode (.class
 files). Bytecode is more compact than Java source code, but it may still
 contain a lot of unused code, especially if it includes program libraries.
 Shrinking programs such as <b>ProGuard</b> can analyze bytecode and remove
 unused classes, fields, and methods. The program remains functionally
 equivalent, including the information given in exception stack traces.

 <h3><a name="obfuscation">What is obfuscation?</a></h3>

 By default, compiled bytecode still contains a lot of debugging information:
 source file names, line numbers, field names, method names, argument names,
 variable names, etc. This information makes it straightforward to decompile
 the bytecode and reverse-engineer entire programs. Sometimes, this is not
 desirable. Obfuscators such as <b>ProGuard</b> can remove the debugging
 information and replace all names by meaningless character sequences, making
 it much harder to reverse-engineer the code. It further compacts the code as a
 bonus. The program remains functionally equivalent, except for the class
 names, method names, and line numbers given in exception stack traces.

 <h3><a name="preverification">What is preverification?</a></h3>

 When loading class files, the class loader performs some sophisticated
 verification of the byte code. This analysis makes sure the code can't
 accidentally or intentionally break out of the sandbox of the virtual machine.
 Java Micro Edition and Java 6 introduced split verification. This means that
 the JME preverifier and the Java 6 compiler add preverification information to
 the class files (StackMap and StackMapTable attributes, respectively), in order
 to simplify the actual verification step for the class loader. Class files can
 then be loaded faster and in a more memory-efficient way. <b>ProGuard</b> can
 perform the preverification step too, for instance allowing to retarget older
 class files at Java 6.

 <h3><a name="optimization">What kind of optimizations does <b>ProGuard</b> support?</a></h3>

 Apart from removing unused classes, fields, and methods in the shrinking step,
 <b>ProGuard</b> can also perform optimizations at the bytecode level, inside
 and across methods. Thanks to techniques like control flow analysis, data flow
 analysis, partial evaluation, static single assignment, global value numbering,
 and liveness analysis, <b>ProGuard</b> can:

 <ul>
 <li>Evaluate constant expressions.</li>
 <li>Remove unnecessary field accesses and method calls.</li>
 <li>Remove unnecessary branches.</li>
 <li>Remove unnecessary comparisons and instanceof tests.</li>
 <li>Remove unused code blocks.</li>
 <li>Merge identical code blocks.</li>
 <li>Reduce variable allocation.</li>
 <li>Remove write-only fields and unused method parameters.</li>
 <li>Inline constant fields, method parameters, and return values.</li>
 <li>Inline methods that are short or only called once.</li>
 <li>Simplify tail recursion calls.</li>
 <li>Merge classes and interfaces.</li>
 <li>Make methods private, static, and final when possible.</li>
 <li>Make classes static and final when possible.</li>
 <li>Replace interfaces that have single implementations.</li>
 <li>Perform over 200 peephole optimizations, like replacing ...*2 by
     ...&lt;&lt;1.</li>
 <li>Optionally remove logging code.</li>
 </ul>
 The positive effects of these optimizations will depend on your code and on
 the virtual machine on which the code is executed. Simple virtual machines may
 benefit more than advanced virtual machines with sophisticated JIT compilers.
 At the very least, your bytecode may become a bit smaller.
 <p>
 Some notable optimizations that aren't supported yet:
 <ul>
 <li>Moving constant expressions out of loops.</li>
 <li>Optimizations that require escape analysis
     (<a href="http://www.guardsquare.com/dexguard" target="_top">DexGuard</a>
     does).</li>
 </ul>

 <h3><a name="commercial">Can I use <b>ProGuard</b> to process my commercial application?</a></h3>

 Yes, you can. <b>ProGuard</b> itself is distributed under the GPL, but this
 doesn't affect the programs that you process. Your code remains yours, and
 its license can remain the same.

 <h3><a name="jdk1.4">Does <b>ProGuard</b> work with Java 2, 5, ..., 8?</a></h3>

 Yes, <b>ProGuard</b> supports all JDKs from 1.1 up to and including 8.0. Java
 2 introduced some small differences in the class file format. Java 5 added
 attributes for generics and for annotations. Java 6 introduced optional
 preverification attributes. Java 7 made preverification obligatory and
 introduced support for dynamic languages. Java 8 added more attributes and
 default methods. <b>ProGuard</b> handles all versions correctly.

 <h3><a name="jme">Does <b>ProGuard</b> work with Java Micro Edition?</a></h3>

 Yes. <b>ProGuard</b> itself runs in Java Standard Edition, but you can freely
 specify the run-time environment at which your programs are targeted,
 including Java Micro Edition. <b>ProGuard</b> then also performs the required
 preverification, producing more compact results than the traditional external
 preverifier.
 <p>
 <b>ProGuard</b> also comes with an obfuscator plug-in for the JME Wireless
 Toolkit.

 <h3><a name="android">Does <b>ProGuard</b> work for Android apps?</a></h3>

 Yes. Google's <code>dx</code> compiler converts Java bytecode into the Dalvik
 bytecode that runs on Android devices. By preprocessing the original
 bytecode, <b>ProGuard</b> can significantly reduce the file sizes and boost
 the run-time performance of the code. It is distributed as part of the Android
 SDK. <a href="http://www.guardsquare.com/dexguard"
 target="_top"><b>DexGuard</b></a>, <b>ProGuard</b>'s closed-source sibling for
 Android, offers additional optimizations and more application protection.

 <h3><a name="blackberry">Does <b>ProGuard</b> work for Blackberry code?</a></h3>

 It should. RIM's proprietary <code>rapc</code> compiler converts ordinary JME
 jar files into cod files that run on Blackberry devices. The compiler performs
 quite a few optimizations, but preprocessing the jar files with
 <b>ProGuard</b> can generally still reduce the final code size by a few
 percent. However, the <code>rapc</code> compiler also seems to contain some
 bugs. It sometimes fails on obfuscated code that is valid and accepted by other
 JME tools and VMs. Your mileage may therefore vary.

 <h3><a name="ant">Does <b>ProGuard</b> have support for Ant?</a></h3>

 Yes. <b>ProGuard</b> provides an Ant task, so that it integrates seamlessly
 into your Ant build process. You can still use configurations in
 <b>ProGuard</b>'s own readable format. Alternatively, if you prefer XML, you
 can specify the equivalent XML configuration.

 <h3><a name="gradle">Does <b>ProGuard</b> have support for Gradle?</a></h3>

 Yes. <b>ProGuard</b> also provides a Gradle task, so that it integrates into
 your Gradle build process. You can specify configurations in
 <b>ProGuard</b>'s own format or embedded in the Groovy configuration.

 <h3><a name="maven">Does <b>ProGuard</b> have support for Maven?</a></h3>

 <b>ProGuard</b>'s jar files are also distributed as artefacts from
 the <a href="http://search.maven.org/#search|ga|1|g:%22net.sf.proguard%22"
 target="other">Maven Central</a> repository. There are some third-party
 plugins that support <b>ProGuard</b>, such as the
 <a href="http://code.google.com/p/maven-android-plugin/"
 target="other">android-maven-plugin</a> and the
 <a href="http://mavenproguard.sourceforge.net/" target="other">IDFC Maven
 ProGuard Plug-in</a>.
 <a href="http://www.guardsquare.com/dexguard" target="_top"><b>DexGuard</b></a>
 also comes with a Maven plugin.

 <h3><a name="gui">Does <b>ProGuard</b> come with a GUI?</a></h3>

 Yes. First of all, <b>ProGuard</b> is perfectly usable as a command-line tool
 that can easily be integrated into any automatic build process. For casual
 users, there's also a graphical user interface that simplifies creating,
 loading, editing, executing, and saving ProGuard configurations.

 <h3><a name="forname">Does <b>ProGuard</b> handle <code>Class.forName</code> calls?</a></h3>

 Yes. <b>ProGuard</b> automatically handles constructs like
 <code>Class.forName("SomeClass")</code> and <code>SomeClass.class</code>. The
 referenced classes are preserved in the shrinking phase, and the string
 arguments are properly replaced in the obfuscation phase.
 <p>
 With variable string arguments, it's generally not possible to determine their
 possible values. They might be read from a configuration file, for instance.
 However, <b>ProGuard</b> will note a number of constructs like
 "<code>(SomeClass)Class.forName(variable).newInstance()</code>". These might
 be an indication that the class or interface <code>SomeClass</code> and/or its
 implementations may need to be preserved. The developer can adapt his
 configuration accordingly.

 <h3><a name="resource">Does <b>ProGuard</b> handle resource files?</a></h3>

 Yes. <b>ProGuard</b> copies all non-class resource files, optionally adapting
 their names and their contents to the obfuscation that has been applied.

 <h3><a name="encrypt">Does <b>ProGuard</b> encrypt string constants?</a></h3>

 No. String encryption in program code has to be perfectly reversible by
 definition, so it only improves the obfuscation level. It increases the
 footprint of the code. However, by popular demand, <b>ProGuard</b>'s
 closed-source sibling for Android, <a href="http://www.guardsquare.com/dexguard"
 target="_top"><b>DexGuard</b></a>, does provide string encryption, along with
 more protection techniques against static and dynamic analysis.

 <h3><a name="flow">Does <b>ProGuard</b> perform control flow obfuscation?</a></h3>

 Not explicitly. Control flow obfuscation injects additional branches into the
 bytecode, in an attempt to fool decompilers. <b>ProGuard</b> does not do this,
 except to some extent in its optimization techniques. <b>ProGuard</b>'s
 closed-source sibling for Android, <a href="http://www.guardsquare.com/dexguard"
 target="_top"><b>DexGuard</b></a>, does offer control flow obfuscation, as one
 of the many additional techniques to harden Android apps.

 <h3><a name="incremental">Does <b>ProGuard</b> support incremental obfuscation?</a></h3>

 Yes. This feature allows you to specify a previous obfuscation mapping file in
 a new obfuscation step, in order to produce add-ons or patches for obfuscated
 code.

 <h3><a name="keywords">Can <b>ProGuard</b> obfuscate using reserved keywords?</a></h3>

 Yes. You can specify your own obfuscation dictionary, such as a list of
 reserved key words, identifiers with foreign characters, random source files,
 or a text by Shakespeare. Note that this hardly improves the obfuscation.
 Decent decompilers can automatically replace reserved keywords, and the effect
 can be undone fairly easily, by obfuscating again with simpler names.

 <h3><a name="stacktrace">Can <b>ProGuard</b> reconstruct obfuscated stack traces?</a></h3>

 Yes. <b>ProGuard</b> comes with a companion tool, <b>ReTrace</b>, that can
 'de-obfuscate' stack traces produced by obfuscated applications. The
 reconstruction is based on the mapping file that <b>ProGuard</b> can write
 out. If line numbers have been obfuscated away, a list of alternative method
 names is presented for each obfuscated method name that has an ambiguous
 reverse mapping. Please refer to the <a href="manual/index.html">ProGuard User
 Manual</a> for more details.
 <p>
 Erik Andr&eacute; at Badoo has written a
 <a href="https://techblog.badoo.com/blog/2014/10/08/deobfuscating-hprof-memory-dumps/"
 target="other">tool to de-obfuscate HPROF memory dumps</a>.

 <h3><a name="dexguard">How is <b>DexGuard</b> different from <b>ProGuard</b>?</a></h3>

 <a href="http://www.guardsquare.com/dexguard"><b>DexGuard</b></a> is a
 commercial extension of <b>ProGuard</b>:
 <ul>
 <li><b>DexGuard</b> is specialized for Android applications and libraries: it
     optimizes and obfuscates not just the bytecode, but also the manifest file,
     resources, resource files, asset files, and native libraries.</li>
 <li><b>DexGuard</b> focuses on making apps self-defending against reverse
     engineering and tampering. <b>DexGuard</b>'s techniques for obfuscation,
     encryption, and detection are a lot stronger than <b>ProGuard</b>'s basic
     name obfuscation.</li>
 <li><b>DexGuard</b> is backward compatible with <b>ProGuard</b>: it reads the
     same configuration. It already comes with tuned configuration for the
     Android runtime and for common Android libraries.</li>
 </ul>

 <hr />
 <address>
 Copyright &copy; 2002-2017
 <a target="other" href="http://www.lafortune.eu/">Eric Lafortune</a> @ <a target="top" href="http://www.guardsquare.com/">GuardSquare</a>.
 </address>
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	<h2>Frequently Asked Questions</h2>

	<h3>Contents</h3>

	<ol>
	<li><a href="#shrinking">What is shrinking?</a></li>
	<li><a href="#obfuscation">What is obfuscation?</a></li>
	<li><a href="#preverification">What is preverification?</a></li>
	<li><a href="#optimization">What kind of optimizations does <b>ProGuard</b>
	support?</a></li>
	<li><a href="#commercial">Can I use <b>ProGuard</b> to process my commercial
	application?</a></li>
	<li><a href="#jdk1.4">Does <b>ProGuard</b> work with Java 2, 5, ..., 8?</a></li>
	<li><a href="#jme">Does <b>ProGuard</b> work with Java Micro Edition?</a></li>
	<li><a href="#android">Does <b>ProGuard</b> work for Android apps?</a></li>
	<li><a href="#blackberry">Does <b>ProGuard</b> work for Blackberry
	code?</a></li>
	<li><a href="#ant">Does <b>ProGuard</b> have support for Ant?</a></li>
	<li><a href="#gradle">Does <b>ProGuard</b> have support for Gradle?</a></li>
	<li><a href="#maven">Does <b>ProGuard</b> have support for Maven?</a></li>
	<li><a href="#gui">Does <b>ProGuard</b> come with a GUI?</a></li>
	<li><a href="#forname">Does <b>ProGuard</b> handle <code>Class.forName</code>
	calls?</a></li>
	<li><a href="#resource">Does <b>ProGuard</b> handle resource files?</a></li>
	<li><a href="#encrypt">Does <b>ProGuard</b> encrypt string constants?</a></li>
	<li><a href="#flow">Does <b>ProGuard</b> perform control flow
	obfuscation?</a></li>
	<li><a href="#incremental">Does <b>ProGuard</b> support incremental
	obfuscation?</a></li>
	<li><a href="#keywords">Can <b>ProGuard</b> obfuscate using reserved
	keywords?</a></li>
	<li><a href="#stacktrace">Can <b>ProGuard</b> reconstruct obfuscated stack
	traces?</a></li>
	<li><a href="#dexguard">How is <b>DexGuard</b> different from
	<b>ProGuard</b>?</a></li>
	</ol>

	<h3><a name="shrinking">What is shrinking?</a></h3>

	Java source code (.java files) is typically compiled to bytecode (.class
	files). Bytecode is more compact than Java source code, but it may still
	contain a lot of unused code, especially if it includes program libraries.
	Shrinking programs such as <b>ProGuard</b> can analyze bytecode and remove
	unused classes, fields, and methods. The program remains functionally
	equivalent, including the information given in exception stack traces.

	<h3><a name="obfuscation">What is obfuscation?</a></h3>

	By default, compiled bytecode still contains a lot of debugging information:
	source file names, line numbers, field names, method names, argument names,
	variable names, etc. This information makes it straightforward to decompile
	the bytecode and reverse-engineer entire programs. Sometimes, this is not
	desirable. Obfuscators such as <b>ProGuard</b> can remove the debugging
	information and replace all names by meaningless character sequences, making
	it much harder to reverse-engineer the code. It further compacts the code as a
	bonus. The program remains functionally equivalent, except for the class
	names, method names, and line numbers given in exception stack traces.

	<h3><a name="preverification">What is preverification?</a></h3>

	When loading class files, the class loader performs some sophisticated
	verification of the byte code. This analysis makes sure the code can't
	accidentally or intentionally break out of the sandbox of the virtual machine.
	Java Micro Edition and Java 6 introduced split verification. This means that
	the JME preverifier and the Java 6 compiler add preverification information to
	the class files (StackMap and StackMapTable attributes, respectively), in order
	to simplify the actual verification step for the class loader. Class files can
	then be loaded faster and in a more memory-efficient way. <b>ProGuard</b> can
	perform the preverification step too, for instance allowing to retarget older
	class files at Java 6.

	<h3><a name="optimization">What kind of optimizations does <b>ProGuard</b> support?</a></h3>

	Apart from removing unused classes, fields, and methods in the shrinking step,
	<b>ProGuard</b> can also perform optimizations at the bytecode level, inside
	and across methods. Thanks to techniques like control flow analysis, data flow
	analysis, partial evaluation, static single assignment, global value numbering,
	and liveness analysis, <b>ProGuard</b> can:

	<ul>
	<li>Evaluate constant expressions.</li>
	<li>Remove unnecessary field accesses and method calls.</li>
	<li>Remove unnecessary branches.</li>
	<li>Remove unnecessary comparisons and instanceof tests.</li>
	<li>Remove unused code blocks.</li>
	<li>Merge identical code blocks.</li>
	<li>Reduce variable allocation.</li>
	<li>Remove write-only fields and unused method parameters.</li>
	<li>Inline constant fields, method parameters, and return values.</li>
	<li>Inline methods that are short or only called once.</li>
	<li>Simplify tail recursion calls.</li>
	<li>Merge classes and interfaces.</li>
	<li>Make methods private, static, and final when possible.</li>
	<li>Make classes static and final when possible.</li>
	<li>Replace interfaces that have single implementations.</li>
	<li>Perform over 200 peephole optimizations, like replacing ...*2 by
	...<<1.</li>
	<li>Optionally remove logging code.</li>
	</ul>
	The positive effects of these optimizations will depend on your code and on
	the virtual machine on which the code is executed. Simple virtual machines may
	benefit more than advanced virtual machines with sophisticated JIT compilers.
	At the very least, your bytecode may become a bit smaller.
	<p>
	Some notable optimizations that aren't supported yet:
	<ul>
	<li>Moving constant expressions out of loops.</li>
	<li>Optimizations that require escape analysis
	(<a href="http://www.guardsquare.com/dexguard" target="_top">DexGuard</a>
	does).</li>
	</ul>

	<h3><a name="commercial">Can I use <b>ProGuard</b> to process my commercial application?</a></h3>

	Yes, you can. <b>ProGuard</b> itself is distributed under the GPL, but this
	doesn't affect the programs that you process. Your code remains yours, and
	its license can remain the same.

	<h3><a name="jdk1.4">Does <b>ProGuard</b> work with Java 2, 5, ..., 8?</a></h3>

	Yes, <b>ProGuard</b> supports all JDKs from 1.1 up to and including 8.0. Java
	2 introduced some small differences in the class file format. Java 5 added
	attributes for generics and for annotations. Java 6 introduced optional
	preverification attributes. Java 7 made preverification obligatory and
	introduced support for dynamic languages. Java 8 added more attributes and
	default methods. <b>ProGuard</b> handles all versions correctly.

	<h3><a name="jme">Does <b>ProGuard</b> work with Java Micro Edition?</a></h3>

	Yes. <b>ProGuard</b> itself runs in Java Standard Edition, but you can freely
	specify the run-time environment at which your programs are targeted,
	including Java Micro Edition. <b>ProGuard</b> then also performs the required
	preverification, producing more compact results than the traditional external
	preverifier.
	<p>
	<b>ProGuard</b> also comes with an obfuscator plug-in for the JME Wireless
	Toolkit.

	<h3><a name="android">Does <b>ProGuard</b> work for Android apps?</a></h3>

	Yes. Google's <code>dx</code> compiler converts Java bytecode into the Dalvik
	bytecode that runs on Android devices. By preprocessing the original
	bytecode, <b>ProGuard</b> can significantly reduce the file sizes and boost
	the run-time performance of the code. It is distributed as part of the Android
	SDK. <a href="http://www.guardsquare.com/dexguard"
	target="_top"><b>DexGuard</b></a>, <b>ProGuard</b>'s closed-source sibling for
	Android, offers additional optimizations and more application protection.

	<h3><a name="blackberry">Does <b>ProGuard</b> work for Blackberry code?</a></h3>

	It should. RIM's proprietary <code>rapc</code> compiler converts ordinary JME
	jar files into cod files that run on Blackberry devices. The compiler performs
	quite a few optimizations, but preprocessing the jar files with
	<b>ProGuard</b> can generally still reduce the final code size by a few
	percent. However, the <code>rapc</code> compiler also seems to contain some
	bugs. It sometimes fails on obfuscated code that is valid and accepted by other
	JME tools and VMs. Your mileage may therefore vary.

	<h3><a name="ant">Does <b>ProGuard</b> have support for Ant?</a></h3>

	Yes. <b>ProGuard</b> provides an Ant task, so that it integrates seamlessly
	into your Ant build process. You can still use configurations in
	<b>ProGuard</b>'s own readable format. Alternatively, if you prefer XML, you
	can specify the equivalent XML configuration.

	<h3><a name="gradle">Does <b>ProGuard</b> have support for Gradle?</a></h3>

	Yes. <b>ProGuard</b> also provides a Gradle task, so that it integrates into
	your Gradle build process. You can specify configurations in
	<b>ProGuard</b>'s own format or embedded in the Groovy configuration.

	<h3><a name="maven">Does <b>ProGuard</b> have support for Maven?</a></h3>

	<b>ProGuard</b>'s jar files are also distributed as artefacts from
	the <a href="http://search.maven.org/#search\|ga\|1\|g:%22net.sf.proguard%22"
	target="other">Maven Central</a> repository. There are some third-party
	plugins that support <b>ProGuard</b>, such as the
	<a href="http://code.google.com/p/maven-android-plugin/"
	target="other">android-maven-plugin</a> and the
	<a href="http://mavenproguard.sourceforge.net/" target="other">IDFC Maven
	ProGuard Plug-in</a>.
	<a href="http://www.guardsquare.com/dexguard" target="_top"><b>DexGuard</b></a>
	also comes with a Maven plugin.

	<h3><a name="gui">Does <b>ProGuard</b> come with a GUI?</a></h3>

	Yes. First of all, <b>ProGuard</b> is perfectly usable as a command-line tool
	that can easily be integrated into any automatic build process. For casual
	users, there's also a graphical user interface that simplifies creating,
	loading, editing, executing, and saving ProGuard configurations.

	<h3><a name="forname">Does <b>ProGuard</b> handle <code>Class.forName</code> calls?</a></h3>

	Yes. <b>ProGuard</b> automatically handles constructs like
	<code>Class.forName("SomeClass")</code> and <code>SomeClass.class</code>. The
	referenced classes are preserved in the shrinking phase, and the string
	arguments are properly replaced in the obfuscation phase.
	<p>
	With variable string arguments, it's generally not possible to determine their
	possible values. They might be read from a configuration file, for instance.
	However, <b>ProGuard</b> will note a number of constructs like
	"<code>(SomeClass)Class.forName(variable).newInstance()</code>". These might
	be an indication that the class or interface <code>SomeClass</code> and/or its
	implementations may need to be preserved. The developer can adapt his
	configuration accordingly.

	<h3><a name="resource">Does <b>ProGuard</b> handle resource files?</a></h3>

	Yes. <b>ProGuard</b> copies all non-class resource files, optionally adapting
	their names and their contents to the obfuscation that has been applied.

	<h3><a name="encrypt">Does <b>ProGuard</b> encrypt string constants?</a></h3>

	No. String encryption in program code has to be perfectly reversible by
	definition, so it only improves the obfuscation level. It increases the
	footprint of the code. However, by popular demand, <b>ProGuard</b>'s
	closed-source sibling for Android, <a href="http://www.guardsquare.com/dexguard"
	target="_top"><b>DexGuard</b></a>, does provide string encryption, along with
	more protection techniques against static and dynamic analysis.

	<h3><a name="flow">Does <b>ProGuard</b> perform control flow obfuscation?</a></h3>

	Not explicitly. Control flow obfuscation injects additional branches into the
	bytecode, in an attempt to fool decompilers. <b>ProGuard</b> does not do this,
	except to some extent in its optimization techniques. <b>ProGuard</b>'s
	closed-source sibling for Android, <a href="http://www.guardsquare.com/dexguard"
	target="_top"><b>DexGuard</b></a>, does offer control flow obfuscation, as one
	of the many additional techniques to harden Android apps.

	<h3><a name="incremental">Does <b>ProGuard</b> support incremental obfuscation?</a></h3>

	Yes. This feature allows you to specify a previous obfuscation mapping file in
	a new obfuscation step, in order to produce add-ons or patches for obfuscated
	code.

	<h3><a name="keywords">Can <b>ProGuard</b> obfuscate using reserved keywords?</a></h3>

	Yes. You can specify your own obfuscation dictionary, such as a list of
	reserved key words, identifiers with foreign characters, random source files,
	or a text by Shakespeare. Note that this hardly improves the obfuscation.
	Decent decompilers can automatically replace reserved keywords, and the effect
	can be undone fairly easily, by obfuscating again with simpler names.

	<h3><a name="stacktrace">Can <b>ProGuard</b> reconstruct obfuscated stack traces?</a></h3>

	Yes. <b>ProGuard</b> comes with a companion tool, <b>ReTrace</b>, that can
	'de-obfuscate' stack traces produced by obfuscated applications. The
	reconstruction is based on the mapping file that <b>ProGuard</b> can write
	out. If line numbers have been obfuscated away, a list of alternative method
	names is presented for each obfuscated method name that has an ambiguous
	reverse mapping. Please refer to the <a href="manual/index.html">ProGuard User
	Manual</a> for more details.
	<p>
	Erik André at Badoo has written a
	<a href="https://techblog.badoo.com/blog/2014/10/08/deobfuscating-hprof-memory-dumps/"
	target="other">tool to de-obfuscate HPROF memory dumps</a>.

	<h3><a name="dexguard">How is <b>DexGuard</b> different from <b>ProGuard</b>?</a></h3>

	<a href="http://www.guardsquare.com/dexguard"><b>DexGuard</b></a> is a
	commercial extension of <b>ProGuard</b>:
	<ul>
	<li><b>DexGuard</b> is specialized for Android applications and libraries: it
	optimizes and obfuscates not just the bytecode, but also the manifest file,
	resources, resource files, asset files, and native libraries.</li>
	<li><b>DexGuard</b> focuses on making apps self-defending against reverse
	engineering and tampering. <b>DexGuard</b>'s techniques for obfuscation,
	encryption, and detection are a lot stronger than <b>ProGuard</b>'s basic
	name obfuscation.</li>
	<li><b>DexGuard</b> is backward compatible with <b>ProGuard</b>: it reads the
	same configuration. It already comes with tuned configuration for the
	Android runtime and for common Android libraries.</li>
	</ul>

	<hr />
	<address>
	Copyright © 2002-2017
	<a target="other" href="http://www.lafortune.eu/">Eric Lafortune</a> @ <a target="top" href="http://www.guardsquare.com/">GuardSquare</a>.
	</address>
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