diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java b/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java
index a3d16b629..801291e4e 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/Renderer.java
@@ -20,8 +20,10 @@ import com.carrotsearch.hppc.ObjectIntMap;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -487,22 +489,17 @@ public class Renderer implements RenderingManager {
     }
 
     private void renderClassMetadata(List<ClassNode> classes) {
-        Set<String> classesRequiringName = new HashSet<>();
-        MethodDependencyInfo getNameMethod = context.getDependencyInfo().getMethod(
-                new MethodReference(Class.class, "getName", String.class));
-        if (getNameMethod != null) {
-            classesRequiringName.addAll(Arrays.asList(getNameMethod.getVariable(0).getClassValueNode().getTypes()));
-        }
-        MethodDependencyInfo getSimpleNameMethod = context.getDependencyInfo().getMethod(
-                new MethodReference(Class.class, "getSimpleName", String.class));
-        if (getSimpleNameMethod != null) {
-            classesRequiringName.addAll(Arrays.asList(
-                    getSimpleNameMethod.getVariable(0).getClassValueNode().getTypes()));
+        if (classes.isEmpty()) {
+            return;
         }
 
+        Set<String> classesRequiringName = findClassesRequiringName();
+
         int start = writer.getOffset();
         try {
             writer.append("$rt_metadata([");
+            ObjectIntMap<String> packageIndexes = generatePackageMetadata(classes, classesRequiringName);
+
             boolean first = true;
             for (ClassNode cls : classes) {
                 if (!first) {
@@ -512,7 +509,12 @@ public class Renderer implements RenderingManager {
                 writer.appendClass(cls.getName()).append(",").ws();
 
                 if (classesRequiringName.contains(cls.getName())) {
-                    writer.append("\"").append(RenderingUtil.escapeString(cls.getName())).append("\"");
+                    String className = cls.getName();
+                    int dotIndex = className.lastIndexOf('.') + 1;
+                    String packageName = className.substring(0, dotIndex);
+                    className = className.substring(dotIndex);
+                    writer.append("\"").append(RenderingUtil.escapeString(className)).append("\"").append(",").ws();
+                    writer.append(String.valueOf(packageIndexes.getOrDefault(packageName, -1)));
                 } else {
                     writer.append("0");
                 }
@@ -566,6 +568,85 @@ public class Renderer implements RenderingManager {
         metadataSize = writer.getOffset() - start;
     }
 
+    private ObjectIntMap<String> generatePackageMetadata(List<ClassNode> classes, Set<String> classesRequiringName)
+            throws IOException {
+        PackageNode root = new PackageNode(null);
+
+        for (ClassNode classNode : classes) {
+            String className = classNode.getName();
+            if (!classesRequiringName.contains(className)) {
+                continue;
+            }
+
+            int dotIndex = className.lastIndexOf('.');
+            if (dotIndex < 0) {
+                continue;
+            }
+
+            addPackageName(root, className.substring(0, dotIndex));
+        }
+
+        ObjectIntMap<String> indexes = new ObjectIntHashMap<>();
+        writer.append(String.valueOf(root.count())).append(",").ws();
+        writePackageStructure(root, -1, "", indexes);
+        writer.softNewLine();
+        return indexes;
+    }
+
+    private int writePackageStructure(PackageNode node, int startIndex, String prefix, ObjectIntMap<String> indexes)
+            throws IOException {
+        int index = startIndex;
+        for (PackageNode child : node.children.values()) {
+            writer.append(String.valueOf(startIndex)).append(",").ws()
+                    .append("\"").append(RenderingUtil.escapeString(child.name)).append("\",").ws();
+            String fullName = prefix + child.name + ".";
+            ++index;
+            indexes.put(fullName, index);
+            index = writePackageStructure(child, index, fullName, indexes);
+        }
+        return index;
+    }
+
+    static class PackageNode {
+        String name;
+        Map<String, PackageNode> children = new HashMap<>();
+
+        PackageNode(String name) {
+            this.name = name;
+        }
+
+        int count() {
+            int result = 0;
+            for (PackageNode child : children.values()) {
+                result += 1 + child.count();
+            }
+            return result;
+        }
+    }
+
+    private void addPackageName(PackageNode node, String name) {
+        String[] parts = name.split("\\.");
+        for (String part : parts) {
+            node = node.children.computeIfAbsent(part, PackageNode::new);
+        }
+    }
+
+    private Set<String> findClassesRequiringName() {
+        Set<String> classesRequiringName = new HashSet<>();
+        MethodDependencyInfo getNameMethod = context.getDependencyInfo().getMethod(
+                new MethodReference(Class.class, "getName", String.class));
+        if (getNameMethod != null) {
+            classesRequiringName.addAll(Arrays.asList(getNameMethod.getVariable(0).getClassValueNode().getTypes()));
+        }
+        MethodDependencyInfo getSimpleNameMethod = context.getDependencyInfo().getMethod(
+                new MethodReference(Class.class, "getSimpleName", String.class));
+        if (getSimpleNameMethod != null) {
+            classesRequiringName.addAll(Arrays.asList(
+                    getSimpleNameMethod.getVariable(0).getClassValueNode().getTypes()));
+        }
+        return classesRequiringName;
+    }
+
     private void collectMethodsToCopyFromInterfaces(ClassReader cls, List<MethodReference> targetList) {
         Set<MethodDescriptor> implementedMethods = new HashSet<>();
         implementedMethods.addAll(targetList.stream().map(method -> method.getDescriptor())
diff --git a/core/src/main/resources/org/teavm/backend/javascript/runtime.js b/core/src/main/resources/org/teavm/backend/javascript/runtime.js
index cb27b8cd5..28ec2be2a 100644
--- a/core/src/main/resources/org/teavm/backend/javascript/runtime.js
+++ b/core/src/main/resources/org/teavm/backend/javascript/runtime.js
@@ -429,23 +429,40 @@ function $rt_putStderr(ch) {
     }
 }
 function $rt_metadata(data) {
-    for (var i = 0; i < data.length; i += 8) {
-        var cls = data[i];
+    var i = 0;
+    var packageCount = data[i++];
+    var packages = new Array(packageCount);
+    for (var j = 0; j < packageCount; ++j) {
+        var prefixIndex = data[i++];
+        var prefix = prefixIndex >= 0 ? packages[prefixIndex] : "";
+        packages[j] = prefix + data[i++] + ".";
+    }
+
+    while (i < data.length) {
+        var cls = data[i++];
         cls.$meta = {};
         var m = cls.$meta;
-        var className = data[i + 1];
+        var className = data[i++];
+
         m.name = className !== 0 ? className : null;
+        if (m.name !== null) {
+            var packageIndex = data[i++];
+            if (packageIndex >= 0) {
+                m.name = packages[packageIndex] + m.name;
+            }
+        }
+
         m.binaryName = "L" + m.name + ";";
-        var superclass = data[i + 2];
+        var superclass = data[i++];
         m.superclass = superclass !== 0 ? superclass : null;
-        m.supertypes = data[i + 3];
+        m.supertypes = data[i++];
         if (m.superclass) {
             m.supertypes.push(m.superclass);
             cls.prototype = Object.create(m.superclass.prototype);
         } else {
             cls.prototype = {};
         }
-        var flags = data[i + 4];
+        var flags = data[i++];
         m.enum = (flags & 16) !== 0;
         m.flags = flags;
         m.primitive = false;
@@ -453,13 +470,13 @@ function $rt_metadata(data) {
         cls.prototype.constructor = cls;
         cls.classObject = null;
 
-        m.accessLevel = data[i + 5];
+        m.accessLevel = data[i++];
 
-        var clinit = data[i + 6];
+        var clinit = data[i++];
         cls.$clinit = clinit !== 0 ? clinit : function() {};
 
-        var virtualMethods = data[i + 7];
-        for (var j = 0; j < virtualMethods.length; j += 2) {
+        var virtualMethods = data[i++];
+        for (j = 0; j < virtualMethods.length; j += 2) {
             var name = virtualMethods[j];
             var func = virtualMethods[j + 1];
             if (typeof name === 'string') {