diff -r 3fc3e7c4fb5c -r 6c04b26f9a9a rt/emul/compact/src/main/java/java/lang/System.java
--- a/rt/emul/compact/src/main/java/java/lang/System.java	Wed Sep 18 11:25:14 2013 +0200
+++ b/rt/emul/compact/src/main/java/java/lang/System.java	Tue Feb 11 13:31:42 2014 +0100
@@ -17,6 +17,13 @@
  */
 package java.lang;
 
+import java.io.BufferedOutputStream;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.util.Properties;
 import org.apidesign.bck2brwsr.core.JavaScriptBody;
 
 /** Poor man's re-implementation of most important System methods.
@@ -45,13 +52,27 @@
     }
 
     public static String getProperty(String name) {
+        if ("os.name".equals(name)) {
+            return userAgent();
+        }
         return null;
     }
     
+    @JavaScriptBody(args = {}, body = "return (typeof navigator !== 'undefined') ? navigator.userAgent : 'unknown';")
+    private static native String userAgent();
+    
     public static String getProperty(String key, String def) {
         return def;
     }
     
+    public static Properties getProperties() {
+        throw new SecurityException();
+    }
+    
+    public static void setProperties(Properties p) {
+        throw new SecurityException();
+    }
+    
     /**
      * Returns the system-dependent line separator string.  It always
      * returns the same value - the initial value of the {@linkplain
@@ -67,4 +88,49 @@
     @JavaScriptBody(args = { "exitCode" }, body = "window.close();")
     public static void exit(int exitCode) {
     }
+    
+    public final static InputStream in;
+
+    public final static PrintStream out;
+
+    public final static PrintStream err;
+    
+    public static void setOut(PrintStream out) {
+        throw new SecurityException();
+    }
+
+    public static void setIn(InputStream in) {
+        throw new SecurityException();
+    }
+
+    public static void setErr(PrintStream err) {
+        throw new SecurityException();
+    }
+    
+    static {
+        in = new ByteArrayInputStream(new byte[0]);
+        out = new PrintStream(new BufferedOutputStream(new SystemStream("log")));
+        err = new PrintStream(new BufferedOutputStream(new SystemStream("warn")));
+    }
+
+    private static final class SystemStream extends OutputStream {
+        private final String method;
+
+        public SystemStream(String method) {
+            this.method = method;
+        }
+
+        @Override
+        public void write(byte b[], int off, int len) throws IOException {
+            write(method, new String(b, off, len, "UTF-8"));
+        }
+
+        @JavaScriptBody(args = { "method", "b" }, body = "if (typeof console !== 'undefined') console[method](b.toString());")
+        private static native void write(String method, String b);
+
+        @Override
+        public void write(int b) throws IOException {
+            write(new byte[] { (byte)b });
+        }
+    } // end of SystemStream
 }