diff --git a/translator/Makefile b/translator/Makefile
index 20e9b2734b..5d8392c831 100644
--- a/translator/Makefile
+++ b/translator/Makefile
@@ -160,6 +160,9 @@ JAVA_SOURCES = \
 	ast/VariableDeclarationFragment.java \
 	ast/VariableDeclarationStatement.java \
 	ast/WhileStatement.java \
+	file/InputFile.java \
+	file/JarredInputFile.java \
+	file/RegularInputFile.java \
 	gen/AbstractSourceGenerator.java \
 	gen/GenerationUnit.java \
 	gen/JavadocGenerator.java \
diff --git a/translator/src/main/java/com/google/devtools/j2objc/BuildClosureQueue.java b/translator/src/main/java/com/google/devtools/j2objc/BuildClosureQueue.java
index 4052b587aa..633c9d133d 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/BuildClosureQueue.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/BuildClosureQueue.java
@@ -79,10 +79,9 @@ private static InputFile getFileForName(String name) {
       return null;
     }
 
-    String sourceName = name.replace('.', File.separatorChar) + ".java";
     InputFile inputFile = null;
     try {
-      inputFile = FileUtil.findOnSourcePath(sourceName);
+      inputFile = FileUtil.findOnSourcePath(name);
     } catch (IOException e) {
       ErrorUtil.warning(e.getMessage());
     }
@@ -92,7 +91,8 @@ private static InputFile getFileForName(String name) {
     }
 
     // Check if the source file is older than the generated header file.
-    File headerSource = new File(Options.getOutputDirectory(), sourceName.replace(".java", ".h"));
+    File headerSource =
+        new File(Options.getOutputDirectory(), name.replace('.', File.separatorChar) + ".h");
     if (headerSource.exists() && inputFile.lastModified() < headerSource.lastModified()) {
       return null;
     }
@@ -100,12 +100,10 @@ private static InputFile getFileForName(String name) {
     return inputFile;
   }
 
-  private static boolean findClassFile(String typeName) {
-    // Zip/jar files always use forward slashes.
-    String path = typeName.replace('.', File.separatorChar) + ".class";
+  private static boolean findClassFile(String name) {
     InputFile f = null;
     try {
-      f = FileUtil.findOnClassPath(path);
+      f = FileUtil.findOnClassPath(name);
     } catch (IOException e) {
       ErrorUtil.warning(e.getMessage());
     }
@@ -114,7 +112,7 @@ private static boolean findClassFile(String typeName) {
     }
     // See if it's a JRE class.
     try {
-      Class.forName(typeName);
+      Class.forName(name);
       return true;
     } catch (ClassNotFoundException e) {
       // Fall-through.
diff --git a/translator/src/main/java/com/google/devtools/j2objc/GenerationBatch.java b/translator/src/main/java/com/google/devtools/j2objc/GenerationBatch.java
index 21a6294f3e..1ec8c69c63 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/GenerationBatch.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/GenerationBatch.java
@@ -128,7 +128,10 @@ private void processJavaFile(String filename) {
       inputFile = new RegularInputFile(filename, filename);
 
       if (!inputFile.exists()) {
-        inputFile = FileUtil.findOnSourcePath(filename);
+        // Convert to a qualified name and search on the sourcepath.
+        String qualifiedName =
+            filename.substring(0, filename.length() - 5).replace(File.separatorChar, '.');
+        inputFile = FileUtil.findOnSourcePath(qualifiedName);
 
         if (inputFile == null) {
           ErrorUtil.error("No such file: " + filename);
diff --git a/translator/src/main/java/com/google/devtools/j2objc/ast/TreeConverter.java b/translator/src/main/java/com/google/devtools/j2objc/ast/TreeConverter.java
index 26e6cf8db8..2766f3b624 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/ast/TreeConverter.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/ast/TreeConverter.java
@@ -29,8 +29,7 @@ public static CompilationUnit convertCompilationUnit(
       org.eclipse.jdt.core.dom.CompilationUnit jdtUnit, InputFile inputFile, String source,
       NameTable.Factory nameTableFactory) {
     return new CompilationUnit(
-        jdtUnit, inputFile, FileUtil.getClassNameFromFilePath(inputFile.getUnitName()), source,
-        nameTableFactory);
+        jdtUnit, inputFile, FileUtil.getMainTypeName(inputFile), source, nameTableFactory);
   }
 
   public static Statement convertStatement(org.eclipse.jdt.core.dom.Statement jdtStatement) {
diff --git a/translator/src/main/java/com/google/devtools/j2objc/file/InputFile.java b/translator/src/main/java/com/google/devtools/j2objc/file/InputFile.java
index d792594d7e..acb16ccdab 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/file/InputFile.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/file/InputFile.java
@@ -52,5 +52,12 @@ public interface InputFile {
    */
   String getUnitName();
 
+  /**
+   * Gets name of the file stripped of any path components.
+   * For example, the basename of "package/path/SourceFile.java" is
+   * "SourceFile.java".
+   */
+  String getBasename();
+
   long lastModified();
 }
diff --git a/translator/src/main/java/com/google/devtools/j2objc/file/JarredInputFile.java b/translator/src/main/java/com/google/devtools/j2objc/file/JarredInputFile.java
index a8effb1ec4..2450008471 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/file/JarredInputFile.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/file/JarredInputFile.java
@@ -71,6 +71,11 @@ public String getUnitName() {
     return internalPath;
   }
 
+  @Override
+  public String getBasename() {
+    return internalPath.substring(internalPath.lastIndexOf('/') + 1);
+  }
+
   @Override
   public long lastModified() {
     return new File(jarPath).lastModified();
diff --git a/translator/src/main/java/com/google/devtools/j2objc/file/RegularInputFile.java b/translator/src/main/java/com/google/devtools/j2objc/file/RegularInputFile.java
index 56a5871b66..4167732dd3 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/file/RegularInputFile.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/file/RegularInputFile.java
@@ -61,6 +61,11 @@ public String getUnitName() {
     return unitPath;
   }
 
+  @Override
+  public String getBasename() {
+    return unitPath.substring(unitPath.lastIndexOf(File.separatorChar) + 1);
+  }
+
   @Override
   public long lastModified() {
     return new File(path).lastModified();
diff --git a/translator/src/main/java/com/google/devtools/j2objc/util/FileUtil.java b/translator/src/main/java/com/google/devtools/j2objc/util/FileUtil.java
index 9f106e1fe4..9447fa46a2 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/util/FileUtil.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/util/FileUtil.java
@@ -40,23 +40,20 @@
  */
 public class FileUtil {
 
-  /**
-   * Gets the name of the file, stripped of any directory or extension.
-   */
-  public static String getClassNameFromFilePath(String sourceFileName) {
-    int begin = sourceFileName.lastIndexOf(File.separatorChar) + 1;
-    // Also check for /, since this may be a jar'd source when translating on Windows.
-    int n = sourceFileName.lastIndexOf('/') + 1;
-    if (n > begin) {
-      begin = n;
+  public static String getMainTypeName(InputFile file) {
+    String basename = file.getBasename();
+    int end = basename.lastIndexOf(".java");
+    if (end == -1) {
+      end = basename.lastIndexOf(".class");
+    }
+    if (end != -1) {
+      basename = basename.substring(0, end);
     }
-    int end = sourceFileName.lastIndexOf(".java");
-    String className = sourceFileName.substring(begin, end);
-    return className;
+    return basename;
   }
 
   public static String getQualifiedMainTypeName(InputFile file, CompilationUnit unit) {
-    String qualifiedName = FileUtil.getClassNameFromFilePath(file.getUnitName());
+    String qualifiedName = getMainTypeName(file);
     PackageDeclaration packageDecl = unit.getPackage();
     if (packageDecl != null) {
       String packageName = packageDecl.getName().getFullyQualifiedName();
@@ -71,8 +68,8 @@ public static String getQualifiedMainTypeName(InputFile file, CompilationUnit un
    * Returns a file guaranteed to exist, or null.
    */
   @Nullable
-  public static InputFile findOnSourcePath(String filename) throws IOException {
-    return findOnPaths(filename, Options.getSourcePathEntries());
+  public static InputFile findOnSourcePath(String qualifiedName) throws IOException {
+    return findOnPaths(qualifiedName, Options.getSourcePathEntries(), ".java");
   }
 
   /**
@@ -81,22 +78,26 @@ public static InputFile findOnSourcePath(String filename) throws IOException {
    * Returns a file guaranteed to exist, or null.
    */
   @Nullable
-  public static InputFile findOnClassPath(String filename) throws IOException {
-    return findOnPaths(filename, Options.getClassPathEntries());
+  public static InputFile findOnClassPath(String qualifiedName) throws IOException {
+    return findOnPaths(qualifiedName, Options.getClassPathEntries(), ".class");
   }
 
-  private static InputFile findOnPaths(String filename, List<String> paths) throws IOException {
+  private static InputFile findOnPaths(
+      String qualifiedName, List<String> paths, String extension) throws IOException {
+    String sourceFileName = qualifiedName.replace('.', File.separatorChar) + extension;
+    // Zip/jar files always use forward slashes.
+    String jarEntryName = qualifiedName.replace('.', '/') + extension;
     for (String pathEntry : paths) {
       File f = new File(pathEntry);
       if (f.isDirectory()) {
         RegularInputFile regularFile = new RegularInputFile(
-            pathEntry + File.separatorChar + filename, filename);
+            pathEntry + File.separatorChar + sourceFileName, sourceFileName);
         if (regularFile.exists()) {
           return regularFile;
         }
       } else {
         // Assume it's a jar file
-        JarredInputFile jarFile = new JarredInputFile(pathEntry, filename);
+        JarredInputFile jarFile = new JarredInputFile(pathEntry, jarEntryName);
         if (jarFile.exists()) {
           return jarFile;
         }
diff --git a/translator/src/main/java/com/google/devtools/j2objc/util/NameTable.java b/translator/src/main/java/com/google/devtools/j2objc/util/NameTable.java
index 0a5ab8f3b5..4062af3b97 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/util/NameTable.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/util/NameTable.java
@@ -888,15 +888,13 @@ public String getPrefix(IPackageBinding packageBinding) {
    */
   private static String getPrefixFromPackageInfoSource(IPackageBinding packageBinding) {
     try {
-      String expectedPackageInfoPath = packageBinding.getName();
+      String qualifiedName = "package-info";
+      String packageName = packageBinding.getName();
       // Path will be null if this is the empty package.
-      if (expectedPackageInfoPath == null) {
-        expectedPackageInfoPath = "package-info.java";
-      } else {
-        expectedPackageInfoPath = expectedPackageInfoPath.replace('.', File.separatorChar)
-            + File.separatorChar + "package-info.java";
+      if (packageName != null) {
+        qualifiedName = packageName + '.' + qualifiedName;
       }
-      InputFile file = FileUtil.findOnSourcePath(expectedPackageInfoPath);
+      InputFile file = FileUtil.findOnSourcePath(qualifiedName);
       if (file != null) {
         String pkgInfo = FileUtil.readFile(file);
         int i = pkgInfo.indexOf("@ObjectiveCName");