Fixed:

  * updated function signature for sendDatagram to accept a byte[] for data
    instead of a String.  this matches the behavior of the sendData() function
    for TCP and prevents mangling of your packets due to UTF-safety problems.
  * updated send_datagram in jeventmachine.rb to call .to_java_bytes on data
    for compatibility with above.

java/src/com/rubyeventmachine/EmReactor.java

@@ -442,8 +442,8 @@ public void setCommInactivityTimeout (long sig, long mills) {
 		Connections.get(sig).setCommInactivityTimeout (mills);
 	}
 
-	public void sendDatagram (long sig, String data, int length, String recipAddress, int recipPort) {
-		sendDatagram (sig, ByteBuffer.wrap(data.getBytes()), recipAddress, recipPort);
+	public void sendDatagram (long sig, byte[] data, int length, String recipAddress, int recipPort) {
+		sendDatagram (sig, ByteBuffer.wrap(data), recipAddress, recipPort);
 	}
 
 	public void sendDatagram (long sig, ByteBuffer bb, String recipAddress, int recipPort) {

lib/jeventmachine.rb

@@ -118,7 +118,7 @@ def self.send_data sig, data, length
     @em.sendData sig, data.to_java_bytes
   end
   def self.send_datagram sig, data, length, address, port
-    @em.sendDatagram sig, data, length, address, port
+    @em.sendDatagram sig, data.to_java_bytes, length, address, port
   end
   def self.connect_server server, port
     bind_connect_server nil, nil, server, port