diff --git a/core/src/main/java/com/threerings/getdown/classpath/cache/GarbageCollector.java b/core/src/main/java/com/threerings/getdown/cache/GarbageCollector.java
similarity index 71%
rename from core/src/main/java/com/threerings/getdown/classpath/cache/GarbageCollector.java
rename to core/src/main/java/com/threerings/getdown/cache/GarbageCollector.java
index c4acd6d..6bd732b 100644
--- a/core/src/main/java/com/threerings/getdown/classpath/cache/GarbageCollector.java
+++ b/core/src/main/java/com/threerings/getdown/cache/GarbageCollector.java
@@ -1,8 +1,11 @@
-package com.threerings.getdown.classpath.cache;
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.cache;
 
 import java.io.File;
-import java.io.FileFilter;
-
 import com.threerings.getdown.util.FileUtil;
 
 /**
@@ -44,38 +47,32 @@ public class GarbageCollector
 
     /**
      * Collect and delete garbage in the native cache. It tries to find a jar file with a matching
-     * lastmodified file, and deletes the entire directory accordingly.
+     * last modified file, and deletes the entire directory accordingly.
      */
-    public static void collectNative (File cacheDir, final long retentionPeriodMillis) {
-        FileUtil.walkDirectChildren(cacheDir, new FileUtil.Visitor() {
-            @Override
-            public void visit(File file) {
-                if (file.isDirectory()) {
-                    // Get all the native jars in the directory (there should only be one though)
-                    File[] nativejars = file.listFiles(new FileFilter() {
-                        @Override
-                        public boolean accept(File pathname) {
-                            return pathname.getAbsolutePath().endsWith(".jar");
-                        }
-                    });
-                    for (File nativejar : nativejars) {
-                        if (nativejar==null || !nativejar.exists()) {
+    public static void collectNative (File cacheDir, final long retentionPeriodMillis)
+    {
+        File[] subdirs = cacheDir.listFiles();
+        if (subdirs != null) {
+            for (File dir : subdirs) {
+                if (dir.isDirectory()) {
+                    // Get all the native jars in the directory (there should only be one)
+                    for (File file : dir.listFiles()) {
+                        if (!file.getName().endsWith(".jar")) {
                             continue;
                         }
-
-                        File cachedFile = getCachedFile(nativejar);
-                        File lastAccessedFile = getLastAccessedFile(nativejar);
-
-                        if (!cachedFile.exists() || !lastAccessedFile.exists() || shouldDelete(lastAccessedFile, retentionPeriodMillis)) {
-                           FileUtil.deleteDirHarder(file);
+                        File cachedFile = getCachedFile(file);
+                        File lastAccessedFile = getLastAccessedFile(file);
+                        if (!cachedFile.exists() || !lastAccessedFile.exists() ||
+                            shouldDelete(lastAccessedFile, retentionPeriodMillis)) {
+                            FileUtil.deleteDirHarder(dir);
                         }
                     }
                 } else {
-                    // @TODO There shouldn't be any loose files in native/ but if there are then what? Delete them?
-                    //  file.delete();
+                    // @TODO There shouldn't be any loose files in native/ but if there are then
+                    // what? Delete them? file.delete();
                 }
             }
-        });
+        }
     }
 
     private static boolean shouldDelete (File lastAccessedFile, long retentionMillis)
diff --git a/core/src/main/java/com/threerings/getdown/classpath/cache/ResourceCache.java b/core/src/main/java/com/threerings/getdown/cache/ResourceCache.java
similarity index 62%
rename from core/src/main/java/com/threerings/getdown/classpath/cache/ResourceCache.java
rename to core/src/main/java/com/threerings/getdown/cache/ResourceCache.java
index d517841..b847e12 100644
--- a/core/src/main/java/com/threerings/getdown/classpath/cache/ResourceCache.java
+++ b/core/src/main/java/com/threerings/getdown/cache/ResourceCache.java
@@ -1,4 +1,9 @@
-package com.threerings.getdown.classpath.cache;
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.cache;
 
 import java.io.File;
 import java.io.IOException;
@@ -14,7 +19,6 @@ public class ResourceCache
     public ResourceCache (File _cacheDir) throws IOException
     {
         this._cacheDir = _cacheDir;
-
         createDirectoryIfNecessary(_cacheDir);
     }
 
@@ -26,34 +30,16 @@ public class ResourceCache
     }
 
     /**
-     * Caches the given file under it's {@code digest}. Same as calling {@link #cacheFile(File, String, boolean)}
-     * with {@code false}
-     * @return the cached file
+     * Caches the given file under its {@code digest}.
+     * @param fileToCache file to cache.
+     * @param cacheSubdir the subdirectory of the cache directory in which to store the cached
+     * file. Usually either {@code digest} or a prefix of {@code digest}.
+     * @param digest a crypto digest of the cached files contents.
+     * @return the cached file.
      */
-    public File cacheFile (File fileToCache, String digest) throws IOException
+    public File cacheFile (File fileToCache, String cacheSubdir, String digest) throws IOException
     {
-        return cacheFile(fileToCache, digest, false);
-    }
-
-    /**
-     * Caches the given file under it's {@code digest}.
-     * @param fileToCache file to cache
-     * @param digest used to determine the name of the directory to store file in
-     * @param useFullHashName if true, the name of the cache directory will not be truncated.
-     *                        This is useful if you need to avoid the possibility of two files
-     *                        sharing a directory.
-     * @return the cached file
-     */
-    public File cacheFile (File fileToCache, String digest, boolean useFullHashName) throws IOException
-    {
-        File cacheLocation;
-
-        if (useFullHashName) {
-            cacheLocation = new File(_cacheDir, digest);
-        } else {
-            cacheLocation = new File(_cacheDir, digest.substring(0, 2));
-
-        }
+        File cacheLocation = new File(_cacheDir, cacheSubdir);
         createDirectoryIfNecessary(cacheLocation);
 
         File cachedFile = new File(cacheLocation, digest + getFileSuffix(fileToCache));
diff --git a/core/src/main/java/com/threerings/getdown/classpath/ClassPaths.java b/core/src/main/java/com/threerings/getdown/classpath/ClassPaths.java
deleted file mode 100644
index 05eb487..0000000
--- a/core/src/main/java/com/threerings/getdown/classpath/ClassPaths.java
+++ /dev/null
@@ -1,72 +0,0 @@
-//
-// Getdown - application installer, patcher and launcher
-// Copyright (C) 2004-2016 Getdown authors
-// https://github.com/threerings/getdown/blob/master/LICENSE
-
-package com.threerings.getdown.classpath;
-
-import java.io.File;
-import java.io.IOException;
-import java.util.LinkedHashSet;
-import java.util.concurrent.TimeUnit;
-
-import com.threerings.getdown.classpath.cache.GarbageCollector;
-import com.threerings.getdown.classpath.cache.ResourceCache;
-import com.threerings.getdown.data.Application;
-import com.threerings.getdown.data.Resource;
-
-public class ClassPaths
-{
-
-    /**
-     * Builds either a default or cached classpath based on {@code app}'s configuration.
-     */
-    public static ClassPath buildClassPath (Application app) throws IOException
-    {
-        return app.useCodeCache() ? buildCachedClassPath(app) : buildDefaultClassPath(app);
-    }
-
-    /**
-     * Builds a {@link ClassPath} instance for {@code app} using the code resources in place in
-     * the app directory.
-     */
-    public static ClassPath buildDefaultClassPath (Application app)
-    {
-        LinkedHashSet<File> classPathEntries = new LinkedHashSet<File>();
-        for (Resource resource: app.getActiveCodeResources()) {
-            classPathEntries.add(resource.getFinalTarget());
-        }
-        return new ClassPath(classPathEntries);
-    }
-
-    /**
-     * Builds a {@link ClassPath} instance for {@code app} by first copying the code resources into
-     * a cache directory and then referencing them from there. This avoids problems with
-     * overwriting in-use classpath elements when the application is later updated. This also
-     * "garbage collects" expired caches if necessary.
-     */
-    public static ClassPath buildCachedClassPath (Application app) throws IOException
-    {
-        File codeCacheDir = new File(app.getAppDir(), Application.CACHE_DIR + "/code");
-
-        // a negative value of code_cache_retention_days allows to clean up the cache forcefully
-        if (app.getCodeCacheRetentionDays() != 0) {
-            runGarbageCollection(app, codeCacheDir);
-        }
-
-        ResourceCache cache = new ResourceCache(codeCacheDir);
-        LinkedHashSet<File> classPathEntries = new LinkedHashSet<>();
-        for (Resource resource: app.getActiveCodeResources()) {
-            File entry = cache.cacheFile(resource.getFinalTarget(), app.getDigest(resource));
-            classPathEntries.add(entry);
-        }
-
-        return new ClassPath(classPathEntries);
-    }
-
-    private static void runGarbageCollection (Application app, File cacheDir)
-    {
-        long retainMillis = TimeUnit.DAYS.toMillis(app.getCodeCacheRetentionDays());
-        GarbageCollector.collect(cacheDir, retainMillis);
-    }
-}
diff --git a/core/src/main/java/com/threerings/getdown/classpath/NativeLibPath.java b/core/src/main/java/com/threerings/getdown/classpath/NativeLibPath.java
deleted file mode 100644
index 9c72468..0000000
--- a/core/src/main/java/com/threerings/getdown/classpath/NativeLibPath.java
+++ /dev/null
@@ -1,83 +0,0 @@
-package com.threerings.getdown.classpath;
-
-import com.threerings.getdown.classpath.cache.GarbageCollector;
-import com.threerings.getdown.classpath.cache.ResourceCache;
-import com.threerings.getdown.data.Application;
-import com.threerings.getdown.data.Resource;
-import com.threerings.getdown.util.FileUtil;
-
-import java.io.File;
-import java.io.IOException;
-import java.util.LinkedHashSet;
-import java.util.List;
-import java.util.concurrent.TimeUnit;
-import java.util.jar.JarFile;
-import static com.threerings.getdown.Log.log;
-
-/**
- * Similar to {@link ClassPath}, except used to represent directories containing native libraries instead.
- */
-public class NativeLibPath extends ClassPath {
-
-    public NativeLibPath(LinkedHashSet<File> entries) {
-        super(entries);
-    }
-
-    /**
-     * Builds a {@link NativeLibPath} instance by first caching all native jars (indicated by
-     * nresource=[native jar]), unpacking them, and referencing the locations of each of the unpacked files.
-     * Also performs garbage collection similar to {@link ClassPaths#buildCachedClassPath}
-     *
-     * @param app                   used to determine native jars and related information
-     * @param addCurrentLibraryPath if true, it adds the locations referenced by
-     *                              {@code System.getProperty("java.library.path")} as well
-     */
-    public static NativeLibPath buildLibsPath(Application app, boolean addCurrentLibraryPath) throws IOException {
-        List<Resource> resources = app.getNativeJars();
-        String[] curPaths = System.getProperty("java.library.path").split(File.pathSeparator);
-        LinkedHashSet<File> nativedirs = new LinkedHashSet<>();
-
-        File nativeCacheDir = new File(app.getAppDir(), Application.CACHE_DIR + "/native");
-        ResourceCache cache = new ResourceCache(nativeCacheDir);
-
-        // negative value forces total garbage collection, 0 avoids garbage collection at all
-        if (app.getCodeCacheRetentionDays() != 0) {
-            runGarbageCollection(app, nativeCacheDir);
-        }
-
-        for (Resource resource : resources) {
-            // Use untruncated directory names because in the off chance that two native jars share a directory AND
-            // contain files with the same names, we'll get overwriting issues when unpacking
-            File cachedFile = cache.cacheFile(resource.getFinalTarget(), app.getDigest(resource), true);
-
-            if (!getUnpackedIndicator(cachedFile).exists()) {
-                try {
-                    FileUtil.unpackJar(new JarFile(cachedFile), cachedFile.getParentFile(), false);
-                    getUnpackedIndicator(cachedFile).createNewFile();
-                } catch (IOException ioe) {
-                    log.warning("Failed to unpack native jar", "File", cachedFile.getAbsolutePath(), ioe);
-                    // Keep going and unpack the other jars...
-                }
-            }
-
-            nativedirs.add(cachedFile.getParentFile());
-        }
-
-        if (addCurrentLibraryPath) {
-            for (String path : curPaths) {
-                nativedirs.add(new File(path));
-            }
-        }
-
-        return new NativeLibPath(nativedirs);
-    }
-
-    private static void runGarbageCollection(Application app, File nativeCacheDir) {
-        long retainMillis = TimeUnit.DAYS.toMillis(app.getCodeCacheRetentionDays());
-        GarbageCollector.collectNative(nativeCacheDir, retainMillis);
-    }
-
-    private static File getUnpackedIndicator(File cachedFile) {
-        return new File(cachedFile.getParent(), cachedFile.getName() + ".unpacked");
-    }
-}
diff --git a/core/src/main/java/com/threerings/getdown/data/Application.java b/core/src/main/java/com/threerings/getdown/data/Application.java
index 66bffbe..8198a7c 100644
--- a/core/src/main/java/com/threerings/getdown/data/Application.java
+++ b/core/src/main/java/com/threerings/getdown/data/Application.java
@@ -23,9 +23,6 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.zip.GZIPInputStream;
 
-import com.threerings.getdown.classpath.ClassPaths;
-import com.threerings.getdown.classpath.ClassPath;
-import com.threerings.getdown.classpath.NativeLibPath;
 import com.threerings.getdown.util.*;
 // avoid ambiguity with java.util.Base64 which we can't use as it's 1.8+
 import com.threerings.getdown.util.Base64;
@@ -55,9 +52,6 @@ public class Application
     /** A special classname that means 'use -jar code.jar' instead of a classname. */
     public static final String MANIFEST_CLASS = "manifest";
 
-    /** Name of directory to store cached files in. */
-    public static final String CACHE_DIR = ".cache";
-
     /** Used to communicate information about the UI displayed when updating the application. */
     public static final class UpdateInterface
     {
@@ -379,19 +373,17 @@ public class Application
     }
 
     /**
-     * Returns all jar resources indicated to contain native library files (.dll, .so etc.)
+     * Returns all resources indicated to contain native library files (.dll, .so, etc.).
      */
-    public List<Resource> getNativeJars() {
-
-        List<Resource> nativeJars = new ArrayList<>();
-
+    public List<Resource> getNativeResources ()
+    {
+        List<Resource> natives = new ArrayList<>();
         for (Resource resource: _resources) {
-            if (resource.isNativeJar()) {
-                nativeJars.add(resource);
+            if (resource.isNative()) {
+                natives.add(resource);
             }
         }
-
-        return nativeJars;
+        return natives;
     }
 
     /**
@@ -702,7 +694,10 @@ public class Application
             parseResources(config, auxgroup + ".ucode", Resource.UNPACK, codes);
             ArrayList<Resource> rsrcs = new ArrayList<>();
             parseResources(config, auxgroup + ".resource", Resource.NORMAL, rsrcs);
+            parseResources(config, auxgroup + ".xresource", Resource.EXEC, rsrcs);
             parseResources(config, auxgroup + ".uresource", Resource.UNPACK, rsrcs);
+            parseResources(config, auxgroup + ".presource", Resource.PRELOAD, rsrcs);
+            parseResources(config, auxgroup + ".nresource", Resource.NATIVE, rsrcs);
             _auxgroups.put(auxgroup, new AuxGroup(auxgroup, codes, rsrcs));
         }
 
@@ -934,12 +929,7 @@ public class Application
         boolean dashJarMode = MANIFEST_CLASS.equals(_class);
 
         // add the -classpath arguments if we're not in -jar mode
-        ClassPath classPath = ClassPaths.buildClassPath(this);
-
-        // get the -Djava.library.path value to pass
-        // @TODO optional getdown.txt parameter to set addCurrentLibraryPath to true or false?
-        NativeLibPath nativeLibPaths = NativeLibPath.buildLibsPath(this, true);
-
+        ClassPath classPath = PathBuilder.buildClassPath(this);
         if (!dashJarMode) {
             args.add("-classpath");
             args.add(classPath.asArgumentString());
@@ -963,8 +953,12 @@ public class Application
         // add the marker indicating the app is running in getdown
         args.add("-D" + Properties.GETDOWN + "=true");
 
-        // set the native library path
-        args.add("-Djava.library.path=" + nativeLibPaths.asArgumentString());
+        // set the native library path if we have native resources
+        // @TODO optional getdown.txt parameter to set addCurrentLibraryPath to true or false?
+        ClassPath javaLibPath = PathBuilder.buildLibsPath(this, true);
+        if (javaLibPath != null) {
+            args.add("-Djava.library.path=" + javaLibPath.asArgumentString());
+        }
 
         // pass along any pass-through arguments
         for (Map.Entry<Object, Object> entry : System.getProperties().entrySet()) {
@@ -1044,7 +1038,7 @@ public class Application
      */
     public void invokeDirect () throws IOException
     {
-        ClassPath classPath = ClassPaths.buildClassPath(this);
+        ClassPath classPath = PathBuilder.buildClassPath(this);
         URL[] jarUrls = classPath.asUrls();
 
         // create custom class loader
diff --git a/core/src/main/java/com/threerings/getdown/classpath/ClassPath.java b/core/src/main/java/com/threerings/getdown/data/ClassPath.java
similarity index 80%
rename from core/src/main/java/com/threerings/getdown/classpath/ClassPath.java
rename to core/src/main/java/com/threerings/getdown/data/ClassPath.java
index d96b712..0777b2f 100644
--- a/core/src/main/java/com/threerings/getdown/classpath/ClassPath.java
+++ b/core/src/main/java/com/threerings/getdown/data/ClassPath.java
@@ -1,4 +1,9 @@
-package com.threerings.getdown.classpath;
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.data;
 
 import java.io.File;
 import java.net.MalformedURLException;
@@ -9,9 +14,9 @@ import java.util.LinkedHashSet;
 import java.util.Set;
 
 /**
- * Represents the class path and it's elements of the application to be launched. The class path can
- * either be represented as an {@link #asArgumentString() argument string} for the java command line
- * or as an {@link #asUrls() array of URLs} to be used by a {@link URLClassLoader}.
+ * Represents the class path and it's elements of the application to be launched. The class path
+ * can either be represented as an {@link #asArgumentString() argument string} for the java command
+ * line or as an {@link #asUrls() array of URLs} to be used by a {@link URLClassLoader}.
  */
 public class ClassPath
 {
diff --git a/core/src/main/java/com/threerings/getdown/data/PathBuilder.java b/core/src/main/java/com/threerings/getdown/data/PathBuilder.java
new file mode 100644
index 0000000..932fe30
--- /dev/null
+++ b/core/src/main/java/com/threerings/getdown/data/PathBuilder.java
@@ -0,0 +1,135 @@
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.data;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.jar.JarFile;
+
+import com.threerings.getdown.cache.GarbageCollector;
+import com.threerings.getdown.cache.ResourceCache;
+import com.threerings.getdown.util.FileUtil;
+import static com.threerings.getdown.Log.log;
+
+public class PathBuilder
+{
+    /** Name of directory to store cached code files in. */
+    public static final String CODE_CACHE_DIR = ".cache";
+
+    /** Name of directory to store cached native resources in. */
+    public static final String NATIVE_CACHE_DIR = ".ncache";
+
+    /**
+     * Builds either a default or cached classpath based on {@code app}'s configuration.
+     */
+    public static ClassPath buildClassPath (Application app) throws IOException
+    {
+        return app.useCodeCache() ? buildCachedClassPath(app) : buildDefaultClassPath(app);
+    }
+
+    /**
+     * Builds a {@link ClassPath} instance for {@code app} using the code resources in place in
+     * the app directory.
+     */
+    public static ClassPath buildDefaultClassPath (Application app)
+    {
+        LinkedHashSet<File> classPathEntries = new LinkedHashSet<File>();
+        for (Resource resource: app.getActiveCodeResources()) {
+            classPathEntries.add(resource.getFinalTarget());
+        }
+        return new ClassPath(classPathEntries);
+    }
+
+    /**
+     * Builds a {@link ClassPath} instance for {@code app} by first copying the code resources into
+     * a cache directory and then referencing them from there. This avoids problems with
+     * overwriting in-use classpath elements when the application is later updated. This also
+     * "garbage collects" expired caches if necessary.
+     */
+    public static ClassPath buildCachedClassPath (Application app) throws IOException
+    {
+        File codeCacheDir = new File(app.getAppDir(), CODE_CACHE_DIR);
+
+        // a negative value of code_cache_retention_days allows to clean up the cache forcefully
+        long retainMillis = TimeUnit.DAYS.toMillis(app.getCodeCacheRetentionDays());
+        if (retainMillis != 0L) {
+            GarbageCollector.collect(codeCacheDir, retainMillis);
+        }
+
+        ResourceCache cache = new ResourceCache(codeCacheDir);
+        LinkedHashSet<File> classPathEntries = new LinkedHashSet<>();
+        for (Resource resource: app.getActiveCodeResources()) {
+            String digest = app.getDigest(resource);
+            File entry = cache.cacheFile(resource.getFinalTarget(), digest.substring(0, 2), digest);
+            classPathEntries.add(entry);
+        }
+
+        return new ClassPath(classPathEntries);
+    }
+
+    /**
+     * Builds a {@link ClassPath} instance by first caching all native jars (indicated by
+     * nresource=[native jar]), unpacking them, and referencing the locations of each of the
+     * unpacked files. Also performs garbage collection similar to {@link #buildCachedClassPath}
+     *
+     * @param app                   used to determine native jars and related information.
+     * @param addCurrentLibraryPath if true, it adds the locations referenced by
+     *                              {@code System.getProperty("java.library.path")} as well.
+     * @return a classpath instance if at least one native resource was found and unpacked,
+     *         {@code null} if no native resources were used by the application.
+     */
+    public static ClassPath buildLibsPath (Application app,
+                                           boolean addCurrentLibraryPath) throws IOException {
+        List<Resource> resources = app.getNativeResources();
+        if (resources.isEmpty()) {
+            return null;
+        }
+
+        LinkedHashSet<File> nativedirs = new LinkedHashSet<>();
+        File nativeCacheDir = new File(app.getAppDir(), NATIVE_CACHE_DIR);
+        ResourceCache cache = new ResourceCache(nativeCacheDir);
+
+        // negative value forces total garbage collection, 0 avoids garbage collection at all
+        long retainMillis = TimeUnit.DAYS.toMillis(app.getCodeCacheRetentionDays());
+        if (retainMillis != 0L) {
+            GarbageCollector.collectNative(nativeCacheDir, retainMillis);
+        }
+
+        for (Resource resource : resources) {
+            // Use untruncated cache subdirectory names to avoid overwriting issues when unpacking,
+            // in the off chance that two native jars share a directory AND contain files with the
+            // same names
+            String digest = app.getDigest(resource);
+            File cachedFile = cache.cacheFile(resource.getFinalTarget(), digest, digest);
+            File cachedParent = cachedFile.getParentFile();
+            File unpackedIndicator = new File(cachedParent, cachedFile.getName() + ".unpacked");
+
+            if (!unpackedIndicator.exists()) {
+                try {
+                    FileUtil.unpackJar(new JarFile(cachedFile), cachedParent, false);
+                    unpackedIndicator.createNewFile();
+                } catch (IOException ioe) {
+                    log.warning("Failed to unpack native jar",
+                                "file", cachedFile.getAbsolutePath(), ioe);
+                    // Keep going and unpack the other jars...
+                }
+            }
+
+            nativedirs.add(cachedFile.getParentFile());
+        }
+
+        if (addCurrentLibraryPath) {
+            for (String path : System.getProperty("java.library.path").split(File.pathSeparator)) {
+                nativedirs.add(new File(path));
+            }
+        }
+
+        return new ClassPath(nativedirs);
+    }
+}
diff --git a/core/src/main/java/com/threerings/getdown/data/Resource.java b/core/src/main/java/com/threerings/getdown/data/Resource.java
index 9d6a040..babfecc 100644
--- a/core/src/main/java/com/threerings/getdown/data/Resource.java
+++ b/core/src/main/java/com/threerings/getdown/data/Resource.java
@@ -46,7 +46,7 @@ public class Resource implements Comparable<Resource>
     public static final EnumSet<Attr> UNPACK  = EnumSet.of(Attr.UNPACK);
     public static final EnumSet<Attr> EXEC    = EnumSet.of(Attr.EXEC);
     public static final EnumSet<Attr> PRELOAD = EnumSet.of(Attr.PRELOAD);
-    public static final EnumSet<Attr> NATIVE = EnumSet.of(Attr.NATIVE);
+    public static final EnumSet<Attr> NATIVE  = EnumSet.of(Attr.NATIVE);
 
     /**
      * Computes the MD5 hash of the supplied file.
@@ -218,12 +218,11 @@ public class Resource implements Comparable<Resource>
     /**
      * Returns true if this resource is a native lib jar.
      */
-    public boolean isNativeJar ()
+    public boolean isNative ()
     {
         return _attrs.contains(Attr.NATIVE);
     }
 
-
     /**
      * Computes the MD5 hash of this resource's underlying file.
      * <em>Note:</em> This is both CPU and I/O intensive.
diff --git a/core/src/main/java/com/threerings/getdown/util/FileUtil.java b/core/src/main/java/com/threerings/getdown/util/FileUtil.java
index d3325af..20fd992 100644
--- a/core/src/main/java/com/threerings/getdown/util/FileUtil.java
+++ b/core/src/main/java/com/threerings/getdown/util/FileUtil.java
@@ -79,20 +79,17 @@ public class FileUtil
 
     /**
      * Force deletes {@code file} and all of its children recursively using {@link #deleteHarder}.
-     * Note that some children may still be deleted even if {@code false} is returned. Also, since {@link #deleteHarder}
-     * is used, the {@code file} could be deleted once the jvm exits even if {@code false} is returned.
+     * Note that some children may still be deleted even if {@code false} is returned. Also, since
+     * {@link #deleteHarder} is used, the {@code file} could be deleted once the jvm exits even if
+     * {@code false} is returned.
      *
-     * @param file file to delete
+     * @param file file to delete.
      * @return true iff {@code file} was successfully deleted.
      */
-    public static boolean deleteDirHarder(File file) {
+    public static boolean deleteDirHarder (File file) {
         if (file.isDirectory()) {
             for (File child : file.listFiles()) {
-                if (child.isDirectory()) {
-                    deleteDirHarder(child);
-                } else {
-                    deleteHarder(child);
-                }
+                deleteDirHarder(child);
             }
         }
         return deleteHarder(file);
@@ -211,7 +208,7 @@ public class FileUtil
     }
 
     /**
-     * Used by {@link #walkTree} and {@link #walkDirectChildren}.
+     * Used by {@link #walkTree}.
      */
     public interface Visitor
     {
@@ -239,21 +236,4 @@ public class FileUtil
             }
         }
     }
-
-    /**
-     * Walks all direct sub-files of {@code root}, calling {@code visitor} on each file.
-     */
-    public static void walkDirectChildren (final File root, Visitor visitor) {
-        File[] children = root.listFiles();
-
-        if (children == null) return;
-        Deque<File> stack = new ArrayDeque<>(Arrays.asList(children));
-        while (!stack.isEmpty()) {
-            File currentFile = stack.pop();
-            if (currentFile.exists()) {
-                visitor.visit(currentFile);
-            }
-        }
-    }
-
 }
diff --git a/core/src/test/java/com/threerings/getdown/classpath/cache/GarbageCollectorTest.java b/core/src/test/java/com/threerings/getdown/cache/GarbageCollectorTest.java
similarity index 89%
rename from core/src/test/java/com/threerings/getdown/classpath/cache/GarbageCollectorTest.java
rename to core/src/test/java/com/threerings/getdown/cache/GarbageCollectorTest.java
index ee86685..6b604cf 100644
--- a/core/src/test/java/com/threerings/getdown/classpath/cache/GarbageCollectorTest.java
+++ b/core/src/test/java/com/threerings/getdown/cache/GarbageCollectorTest.java
@@ -1,4 +1,9 @@
-package com.threerings.getdown.classpath.cache;
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.cache;
 
 import java.io.File;
 import java.io.IOException;
diff --git a/core/src/test/java/com/threerings/getdown/classpath/cache/ResourceCacheTest.java b/core/src/test/java/com/threerings/getdown/cache/ResourceCacheTest.java
similarity index 88%
rename from core/src/test/java/com/threerings/getdown/classpath/cache/ResourceCacheTest.java
rename to core/src/test/java/com/threerings/getdown/cache/ResourceCacheTest.java
index 8002f0b..8b699bf 100644
--- a/core/src/test/java/com/threerings/getdown/classpath/cache/ResourceCacheTest.java
+++ b/core/src/test/java/com/threerings/getdown/cache/ResourceCacheTest.java
@@ -1,4 +1,9 @@
-package com.threerings.getdown.classpath.cache;
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.cache;
 
 import java.io.File;
 import java.io.IOException;
@@ -26,7 +31,7 @@ public class ResourceCacheTest
 
     private File cacheFile() throws IOException
     {
-        return _cache.cacheFile(_fileToCache, "abc123");
+        return _cache.cacheFile(_fileToCache, "abc123", "abc123");
     }
 
     @Test public void shouldTrackFileUsage () throws IOException
diff --git a/core/src/test/java/com/threerings/getdown/classpath/ClassPathTest.java b/core/src/test/java/com/threerings/getdown/data/ClassPathTest.java
similarity index 87%
rename from core/src/test/java/com/threerings/getdown/classpath/ClassPathTest.java
rename to core/src/test/java/com/threerings/getdown/data/ClassPathTest.java
index fb90a80..1779f64 100644
--- a/core/src/test/java/com/threerings/getdown/classpath/ClassPathTest.java
+++ b/core/src/test/java/com/threerings/getdown/data/ClassPathTest.java
@@ -1,4 +1,9 @@
-package com.threerings.getdown.classpath;
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.data;
 
 import java.io.File;
 import java.io.IOException;
diff --git a/core/src/test/java/com/threerings/getdown/classpath/ClassPathsTest.java b/core/src/test/java/com/threerings/getdown/data/PathBuilderTest.java
similarity index 79%
rename from core/src/test/java/com/threerings/getdown/classpath/ClassPathsTest.java
rename to core/src/test/java/com/threerings/getdown/data/PathBuilderTest.java
index 05b47a1..5bdbcad 100644
--- a/core/src/test/java/com/threerings/getdown/classpath/ClassPathsTest.java
+++ b/core/src/test/java/com/threerings/getdown/data/PathBuilderTest.java
@@ -1,4 +1,9 @@
-package com.threerings.getdown.classpath;
+//
+// Getdown - application installer, patcher and launcher
+// Copyright (C) 2004-2016 Getdown authors
+// https://github.com/threerings/getdown/blob/master/LICENSE
+
+package com.threerings.getdown.data;
 
 import java.io.File;
 import java.io.IOException;
@@ -14,11 +19,8 @@ import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
 import static org.mockito.Mockito.when;
 
-import com.threerings.getdown.data.Application;
-import com.threerings.getdown.data.Resource;
-
 @RunWith(MockitoJUnitRunner.class)
-public class ClassPathsTest
+public class PathBuilderTest
 {
     @Before public void setupFilesAndResources () throws IOException
     {
@@ -33,7 +35,7 @@ public class ClassPathsTest
 
     @Test public void shouldBuildDefaultClassPath () throws IOException
     {
-        ClassPath classPath = ClassPaths.buildDefaultClassPath(_application);
+        ClassPath classPath = PathBuilder.buildDefaultClassPath(_application);
         String expectedClassPath = _firstJarFile.getAbsolutePath() + File.pathSeparator +
             _secondJarFile.getAbsolutePath();
         assertEquals(expectedClassPath, classPath.asArgumentString());
@@ -46,15 +48,15 @@ public class ClassPathsTest
         when(_application.getCodeCacheRetentionDays()).thenReturn(1);
 
         Path firstCachedJarFile = _appdir.getRoot().toPath().
-            resolve(Application.CACHE_DIR + "/code").resolve("fi").resolve("first.jar");
+            resolve(PathBuilder.CODE_CACHE_DIR).resolve("fi").resolve("first.jar");
 
         Path secondCachedJarFile = _appdir.getRoot().toPath().
-            resolve(Application.CACHE_DIR + "/code").resolve("se").resolve("second.jar");
+            resolve(PathBuilder.CODE_CACHE_DIR).resolve("se").resolve("second.jar");
 
         String expectedClassPath = firstCachedJarFile.toAbsolutePath() + File.pathSeparator +
             secondCachedJarFile.toAbsolutePath();
 
-        ClassPath classPath = ClassPaths.buildCachedClassPath(_application);
+        ClassPath classPath = PathBuilder.buildCachedClassPath(_application);
         assertEquals(expectedClassPath, classPath.asArgumentString());
     }