Obfuscating a NetBeans Java Application Project

Some time ago I found a couple of posts talking about how to obfuscate a NetBeans RCP module (here and here).

Getting some parts of the ant targets presented in the previous post, this one presents a simple target that allows to obfuscate a normal Java library.

For this, you need to have installed the obfuscator ProGuard.

Take into account I am talking about obfuscating a Java library. This implies the obfuscation is lighter than if you obfuscate a closed application, that is, all public methods and interfaces must maintain its name (if not you can call your library methods anymore).

Open your build.xml Java application file and paste this target:

    <target name="-post-jar">
        <property name="proguard.jar.path" value="/path/to/proguard.jar" />
        <property name="java.home.path" value="/path/to/java/home" />
        
        <taskdef resource="proguard/ant/task.properties"
                 classpath="${proguard.jar.path}" />
        
        <echo message="Obfuscating ${dist.jar}..."/>
        <mkdir dir="${build.dir}/obfuscated"/>
        <proguard printmapping="${build.dir}/obfuscated/${application.title}.map"
                  renamesourcefileattribute="SourceFile" ignorewarnings="true">
            
            <!-- Specify the input jars, output jars, and library jars. -->
            <injar  file="${dist.jar}" />
            <outjar file="${build.dir}/obfuscated/BalloonWindCore_JavaSE.jar" />
            
            <libraryjar path="${javac.classpath}" />            
            <libraryjar file="${java.home.path}/jre/lib/rt.jar" />
            
            <!-- Keep some useful attributes. -->

            <keepattribute name="InnerClasses" />
            <keepattribute name="SourceFile" />
            <keepattribute name="LineNumberTable" />
            <keepattribute name="Deprecated" />
            <keepattribute name="*Annotation*" />
            <keepattribute name="Signature" />
            
            <!-- Preserve all public classes, and their public and protected fields and methods. -->

            <keep access="public">
                <field  access="public protected" />
                <method access="public protected" />
            </keep>
            
            
            <!-- Preserve all .class method names. -->

            <keepclassmembernames access="public">
                <method type      ="java.lang.Class"
                        name      ="class$"
                        parameters="java.lang.String" />
                <method type      ="java.lang.Class"
                        name      ="class$"
                        parameters="java.lang.String,boolean" />
            </keepclassmembernames>
            
            <!-- Preserve all native method names and the names of their classes. -->

            <keepclasseswithmembernames>
                <method access="native" />
            </keepclasseswithmembernames>
            
            <!-- Preserve the methods that are required in all enumeration classes. -->

            <keepclassmembers extends="java.lang.Enum">
                <method access="public static"
                        type="**[]"
                        name="values"
                        parameters="" />
                <method access="public static"
                        type="**"
                        name="valueOf"
                        parameters="java.lang.String" />
            </keepclassmembers>
            
            <!-- Explicitly preserve all serialization members. The Serializable
                 interface is only a marker interface, so it wouldn't save them.
                 You can comment this out if your library doesn't use serialization.
                 With this code serializable classes will be backward compatible -->

            <keepnames implements="java.io.Serializable"/>
            <keepclassmembers implements="java.io.Serializable">
                <field  access    ="final"
                        type      ="long"
                        name      ="serialVersionUID" />
                <field  access    ="!static !transient"
                        name      ="**"/>
                <field  access    ="!private"
                        name      ="**"/>
                <method access    ="!private"
                        name      ="**"/>
                <method access    ="private"
                        type      ="void"
                        name      ="writeObject"
                        parameters="java.io.ObjectOutputStream" />
                <method access    ="private"
                        type      ="void"
                        name      ="readObject"
                        parameters="java.io.ObjectOutputStream" />
                <method type      ="java.lang.Object"
                        name      ="writeReplace"
                        parameters="" />
                <method type      ="java.lang.Object"
                        name      ="readResolve"
                        parameters="" />
            </keepclassmembers>
            
            <!-- Your application may contain more items that need to be preserved;
                 typically classes that are dynamically created using Class.forName -->

        </proguard>
    </target>

Special attention to these couple of lines:

        <property name="proguard.jar.path" value="/path/to/proguard.jar" />
        <property name="java.home.path" value="/path/to/java/home" />