diff --git a/playwright/src/main/java/com/microsoft/playwright/Browser.java b/playwright/src/main/java/com/microsoft/playwright/Browser.java
index 3e94fac9..2cfcb338 100644
--- a/playwright/src/main/java/com/microsoft/playwright/Browser.java
+++ b/playwright/src/main/java/com/microsoft/playwright/Browser.java
@@ -18,6 +18,7 @@ package com.microsoft.playwright;
 
 import java.nio.file.Path;
 import java.util.*;
+import java.util.function.Consumer;
 
 /**
  * - extends: [EventEmitter]
@@ -44,8 +45,8 @@ public interface Browser {
   }
 
 
-  void onDisconnected(Runnable handler);
-  void offDisconnected(Runnable handler);
+  void onDisconnected(Consumer<Browser> handler);
+  void offDisconnected(Consumer<Browser> handler);
 
 
   class NewContextOptions {
diff --git a/playwright/src/main/java/com/microsoft/playwright/BrowserContext.java b/playwright/src/main/java/com/microsoft/playwright/BrowserContext.java
index 17d1e208..86c41d3a 100644
--- a/playwright/src/main/java/com/microsoft/playwright/BrowserContext.java
+++ b/playwright/src/main/java/com/microsoft/playwright/BrowserContext.java
@@ -95,8 +95,8 @@ public interface BrowserContext {
   }
 
 
-  void onClose(Runnable handler);
-  void offClose(Runnable handler);
+  void onClose(Consumer<BrowserContext> handler);
+  void offClose(Consumer<BrowserContext> handler);
 
   void onPage(Consumer<Page> handler);
   void offPage(Consumer<Page> handler);
diff --git a/playwright/src/main/java/com/microsoft/playwright/Page.java b/playwright/src/main/java/com/microsoft/playwright/Page.java
index e7156227..fe862fca 100644
--- a/playwright/src/main/java/com/microsoft/playwright/Page.java
+++ b/playwright/src/main/java/com/microsoft/playwright/Page.java
@@ -75,20 +75,20 @@ public interface Page {
   }
 
 
-  void onClose(Runnable handler);
-  void offClose(Runnable handler);
+  void onClose(Consumer<Page> handler);
+  void offClose(Consumer<Page> handler);
 
   void onConsole(Consumer<ConsoleMessage> handler);
   void offConsole(Consumer<ConsoleMessage> handler);
 
-  void onCrash(Runnable handler);
-  void offCrash(Runnable handler);
+  void onCrash(Consumer<Page> handler);
+  void offCrash(Consumer<Page> handler);
 
   void onDialog(Consumer<Dialog> handler);
   void offDialog(Consumer<Dialog> handler);
 
-  void onDomContentLoaded(Runnable handler);
-  void offDomContentLoaded(Runnable handler);
+  void onDOMContentLoaded(Consumer<Page> handler);
+  void offDOMContentLoaded(Consumer<Page> handler);
 
   void onDownload(Consumer<Download> handler);
   void offDownload(Consumer<Download> handler);
@@ -105,8 +105,8 @@ public interface Page {
   void onFrameNavigated(Consumer<Frame> handler);
   void offFrameNavigated(Consumer<Frame> handler);
 
-  void onLoad(Runnable handler);
-  void offLoad(Runnable handler);
+  void onLoad(Consumer<Page> handler);
+  void offLoad(Consumer<Page> handler);
 
   void onPageError(Consumer<Error> handler);
   void offPageError(Consumer<Error> handler);
diff --git a/playwright/src/main/java/com/microsoft/playwright/WebSocket.java b/playwright/src/main/java/com/microsoft/playwright/WebSocket.java
index 25f5155d..74df323d 100644
--- a/playwright/src/main/java/com/microsoft/playwright/WebSocket.java
+++ b/playwright/src/main/java/com/microsoft/playwright/WebSocket.java
@@ -30,8 +30,8 @@ public interface WebSocket {
   }
 
 
-  void onClose(Runnable handler);
-  void offClose(Runnable handler);
+  void onClose(Consumer<WebSocket> handler);
+  void offClose(Consumer<WebSocket> handler);
 
   void onFrameReceived(Consumer<FrameData> handler);
   void offFrameReceived(Consumer<FrameData> handler);
diff --git a/playwright/src/main/java/com/microsoft/playwright/impl/BrowserContextImpl.java b/playwright/src/main/java/com/microsoft/playwright/impl/BrowserContextImpl.java
index 6d2ffca8..ab2e18eb 100644
--- a/playwright/src/main/java/com/microsoft/playwright/impl/BrowserContextImpl.java
+++ b/playwright/src/main/java/com/microsoft/playwright/impl/BrowserContextImpl.java
@@ -60,12 +60,12 @@ class BrowserContextImpl extends ChannelOwner implements BrowserContext {
   }
 
   @Override
-  public void onClose(Runnable handler) {
+  public void onClose(Consumer<BrowserContext> handler) {
     listeners.add(EventType.CLOSE, handler);
   }
 
   @Override
-  public void offClose(Runnable handler) {
+  public void offClose(Consumer<BrowserContext> handler) {
     listeners.remove(EventType.CLOSE, handler);
   }
 
@@ -416,7 +416,7 @@ class BrowserContextImpl extends ChannelOwner implements BrowserContext {
       if (browser != null) {
         browser.contexts.remove(this);
       }
-      listeners.notify(EventType.CLOSE, null);
+      listeners.notify(EventType.CLOSE, this);
     }
   }
 }
diff --git a/playwright/src/main/java/com/microsoft/playwright/impl/BrowserImpl.java b/playwright/src/main/java/com/microsoft/playwright/impl/BrowserImpl.java
index 3db461de..0869968b 100644
--- a/playwright/src/main/java/com/microsoft/playwright/impl/BrowserImpl.java
+++ b/playwright/src/main/java/com/microsoft/playwright/impl/BrowserImpl.java
@@ -27,6 +27,7 @@ import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.function.Consumer;
 
 import static com.microsoft.playwright.impl.Serialization.gson;
 import static com.microsoft.playwright.impl.Utils.convertViaJson;
@@ -46,12 +47,12 @@ class BrowserImpl extends ChannelOwner implements Browser {
   }
 
   @Override
-  public void onDisconnected(Runnable handler) {
+  public void onDisconnected(Consumer<Browser> handler) {
     listeners.add(EventType.DISCONNECTED, handler);
   }
 
   @Override
-  public void offDisconnected(Runnable handler) {
+  public void offDisconnected(Consumer<Browser> handler) {
     listeners.remove(EventType.DISCONNECTED, handler);
   }
 
@@ -136,7 +137,7 @@ class BrowserImpl extends ChannelOwner implements Browser {
   void handleEvent(String event, JsonObject parameters) {
     if ("close".equals(event)) {
       isConnected = false;
-      listeners.notify(EventType.DISCONNECTED, null);
+      listeners.notify(EventType.DISCONNECTED, this);
     }
   }
 }
diff --git a/playwright/src/main/java/com/microsoft/playwright/impl/ListenerCollection.java b/playwright/src/main/java/com/microsoft/playwright/impl/ListenerCollection.java
index 49c083de..4bfc8d60 100644
--- a/playwright/src/main/java/com/microsoft/playwright/impl/ListenerCollection.java
+++ b/playwright/src/main/java/com/microsoft/playwright/impl/ListenerCollection.java
@@ -47,32 +47,6 @@ class ListenerCollection <EventType> {
     }
   }
 
-  private static class RunnableWrapper<EventType> implements Listener<EventType> {
-    final Runnable callback;
-
-    private RunnableWrapper(Runnable callback) {
-      this.callback = callback;
-    }
-
-    @Override
-    public void handle(Event<EventType> event) {
-      callback.run();
-    }
-
-    @Override
-    public boolean equals(Object o) {
-      if (this == o) return true;
-      if (o == null || getClass() != o.getClass()) return false;
-      RunnableWrapper<?> that = (RunnableWrapper<?>) o;
-      return Objects.equals(callback, that.callback);
-    }
-
-    @Override
-    public int hashCode() {
-      return Objects.hash(callback);
-    }
-  }
-
   private static class ConsumerWrapper<EventType> implements Listener<EventType> {
     final Consumer<?> callback;
 
@@ -98,13 +72,6 @@ class ListenerCollection <EventType> {
     }
   }
 
-  void add(EventType type, Runnable listener) {
-    add(type, new RunnableWrapper<>(listener));
-  }
-  void remove(EventType type, Runnable listener) {
-    remove(type, new RunnableWrapper<>(listener));
-  }
-
   void add(EventType type, Consumer listener) {
     add(type, new ConsumerWrapper<>(listener));
   }
diff --git a/playwright/src/main/java/com/microsoft/playwright/impl/PageImpl.java b/playwright/src/main/java/com/microsoft/playwright/impl/PageImpl.java
index 576def2c..0277d3c3 100644
--- a/playwright/src/main/java/com/microsoft/playwright/impl/PageImpl.java
+++ b/playwright/src/main/java/com/microsoft/playwright/impl/PageImpl.java
@@ -155,9 +155,9 @@ public class PageImpl extends ChannelOwner implements Page {
         }
       }
     } else if ("load".equals(event)) {
-      listeners.notify(EventType.LOAD, null);
+      listeners.notify(EventType.LOAD, this);
     } else if ("domcontentloaded".equals(event)) {
-      listeners.notify(EventType.DOMCONTENTLOADED, null);
+      listeners.notify(EventType.DOMCONTENTLOADED, this);
     } else if ("request".equals(event)) {
       String guid = params.getAsJsonObject("request").get("guid").getAsString();
       Request request = connection.getExistingObject(guid);
@@ -210,11 +210,11 @@ public class PageImpl extends ChannelOwner implements Page {
       SerializedError error = gson().fromJson(params.getAsJsonObject("error"), SerializedError.class);
       listeners.notify(EventType.PAGEERROR, new ErrorImpl(error));
     } else if ("crash".equals(event)) {
-      listeners.notify(EventType.CRASH, null);
+      listeners.notify(EventType.CRASH, this);
     } else if ("close".equals(event)) {
       isClosed = true;
       browserContext.pages.remove(this);
-      listeners.notify(EventType.CLOSE, null);
+      listeners.notify(EventType.CLOSE, this);
     }
   }
 
@@ -237,12 +237,12 @@ public class PageImpl extends ChannelOwner implements Page {
   }
 
   @Override
-  public void onClose(Runnable handler) {
+  public void onClose(Consumer<Page> handler) {
     listeners.add(EventType.CLOSE, handler);
   }
 
   @Override
-  public void offClose(Runnable handler) {
+  public void offClose(Consumer<Page> handler) {
     listeners.remove(EventType.CLOSE, handler);
   }
 
@@ -257,12 +257,12 @@ public class PageImpl extends ChannelOwner implements Page {
   }
 
   @Override
-  public void onCrash(Runnable handler) {
+  public void onCrash(Consumer<Page> handler) {
     listeners.add(EventType.CRASH, handler);
   }
 
   @Override
-  public void offCrash(Runnable handler) {
+  public void offCrash(Consumer<Page> handler) {
     listeners.remove(EventType.CRASH, handler);
   }
 
@@ -277,12 +277,12 @@ public class PageImpl extends ChannelOwner implements Page {
   }
 
   @Override
-  public void onDomContentLoaded(Runnable handler) {
+  public void onDOMContentLoaded(Consumer<Page> handler) {
     listeners.add(EventType.DOMCONTENTLOADED, handler);
   }
 
   @Override
-  public void offDomContentLoaded(Runnable handler) {
+  public void offDOMContentLoaded(Consumer<Page> handler) {
     listeners.remove(EventType.DOMCONTENTLOADED, handler);
   }
 
@@ -337,12 +337,12 @@ public class PageImpl extends ChannelOwner implements Page {
   }
 
   @Override
-  public void onLoad(Runnable handler) {
+  public void onLoad(Consumer<Page> handler) {
     listeners.add(EventType.LOAD, handler);
   }
 
   @Override
-  public void offLoad(Runnable handler) {
+  public void offLoad(Consumer<Page> handler) {
     listeners.remove(EventType.LOAD, handler);
   }
 
diff --git a/playwright/src/main/java/com/microsoft/playwright/impl/WebSocketImpl.java b/playwright/src/main/java/com/microsoft/playwright/impl/WebSocketImpl.java
index 15715a61..d2a1bf24 100644
--- a/playwright/src/main/java/com/microsoft/playwright/impl/WebSocketImpl.java
+++ b/playwright/src/main/java/com/microsoft/playwright/impl/WebSocketImpl.java
@@ -44,12 +44,12 @@ class WebSocketImpl extends ChannelOwner implements WebSocket {
   }
 
   @Override
-  public void onClose(Runnable handler) {
+  public void onClose(Consumer<WebSocket> handler) {
     listeners.add(EventType.CLOSE, handler);
   }
 
   @Override
-  public void offClose(Runnable handler) {
+  public void offClose(Consumer<WebSocket> handler) {
     listeners.remove(EventType.CLOSE, handler);
   }
 
@@ -212,7 +212,7 @@ class WebSocketImpl extends ChannelOwner implements WebSocket {
       }
       case "close": {
         isClosed = true;
-        listeners.notify(EventType.CLOSE, null);
+        listeners.notify(EventType.CLOSE, this);
         break;
       }
       default: {
diff --git a/playwright/src/test/java/com/microsoft/playwright/TestDefaultBrowserContext2.java b/playwright/src/test/java/com/microsoft/playwright/TestDefaultBrowserContext2.java
index 5a79b02d..a5c99bf3 100644
--- a/playwright/src/test/java/com/microsoft/playwright/TestDefaultBrowserContext2.java
+++ b/playwright/src/test/java/com/microsoft/playwright/TestDefaultBrowserContext2.java
@@ -223,7 +223,7 @@ public class TestDefaultBrowserContext2 extends TestBase {
   void shouldFireCloseEventForAPersistentContext() {
     launchPersistent();
     boolean[] closed = {false};
-    persistentContext.onClose(() -> closed[0] = true);
+    persistentContext.onClose(context -> closed[0] = true);
     closePersistentContext();
     assertTrue(closed[0]);
   }
diff --git a/playwright/src/test/java/com/microsoft/playwright/TestWebSocket.java b/playwright/src/test/java/com/microsoft/playwright/TestWebSocket.java
index 02811bae..16e7718a 100644
--- a/playwright/src/test/java/com/microsoft/playwright/TestWebSocket.java
+++ b/playwright/src/test/java/com/microsoft/playwright/TestWebSocket.java
@@ -101,7 +101,7 @@ public class TestWebSocket extends TestBase {
     page.onWebSocket(ws -> {
       log.add("open<" + ws.url() + ">");
       webSocket[0] = ws;
-      ws.onClose(() -> {
+      ws.onClose(ws1 -> {
         log.add("close");
         socketClosed[0] = true;
       });
@@ -123,7 +123,7 @@ public class TestWebSocket extends TestBase {
       log.add("open");
       ws.onFrameSent(frameData -> log.add("sent<" + frameData.text() + ">"));
       ws.onFrameReceived(frameData -> log.add("received<" + frameData.text()  + ">"));
-      ws.onClose(() -> { log.add("close"); socketClosed[0] = true; });
+      ws.onClose(ws1 -> { log.add("close"); socketClosed[0] = true; });
     });
     page.evaluate("port => {\n" +
       "    const ws = new WebSocket('ws://localhost:' + port + '/ws');\n" +
@@ -146,7 +146,7 @@ public class TestWebSocket extends TestBase {
     boolean[] socketClosed = {false};
     List<com.microsoft.playwright.WebSocket.FrameData> sent = new ArrayList<>();
     page.onWebSocket(ws -> {
-      ws.onClose(() -> { socketClosed[0] = true; });
+      ws.onClose(ws1 -> socketClosed[0] = true);
       ws.onFrameSent(frameData -> sent.add(frameData));
     });
     page.evaluate("port => {\n" +
diff --git a/tools/api-generator/src/main/java/com/microsoft/playwright/tools/ApiGenerator.java b/tools/api-generator/src/main/java/com/microsoft/playwright/tools/ApiGenerator.java
index 9f132dae..5be3d003 100644
--- a/tools/api-generator/src/main/java/com/microsoft/playwright/tools/ApiGenerator.java
+++ b/tools/api-generator/src/main/java/com/microsoft/playwright/tools/ApiGenerator.java
@@ -375,7 +375,7 @@ class Event extends Element {
     eventNames.put("Page.console", "Console");
     eventNames.put("Page.crash", "Crash");
     eventNames.put("Page.dialog", "Dialog");
-    eventNames.put("Page.domcontentloaded", "DomContentLoaded");
+    eventNames.put("Page.domcontentloaded", "DOMContentLoaded");
     eventNames.put("Page.download", "Download");
     eventNames.put("Page.filechooser", "FileChooser");
     eventNames.put("Page.frameattached", "FrameAttached");
@@ -438,7 +438,12 @@ class Event extends Element {
       throw new RuntimeException("Unknown event: " + jsonPath);
     }
     String name = eventNames.get(jsonPath);
-    String listenerType = "void".equals(type.toJava()) ? "Runnable" : "Consumer<" + type.toJava() + ">";
+    String paramType = type.toJava();
+    // TODO: remove once fixed upstream
+    if (paramType.equals("void")) {
+      paramType = parent.jsonName;
+    }
+    String listenerType = "Consumer<" + paramType + ">";
     output.add(offset + "void on" + name + "(" + listenerType + " handler);");
     output.add(offset + "void off" + name + "(" + listenerType + " handler);");
   }
@@ -1050,7 +1055,7 @@ class Interface extends TypeDefinition {
       output.add("import java.nio.file.Path;");
     }
     output.add("import java.util.*;");
-    if (asList("Page", "BrowserContext", "WebSocket", "Worker").contains(jsonName)) {
+    if (asList("Page", "Browser", "BrowserContext", "WebSocket", "Worker").contains(jsonName)) {
       output.add("import java.util.function.Consumer;");
     }
     if (asList("Page", "Frame", "BrowserContext", "WebSocket").contains(jsonName)) {