Notifo4j is a project mainly written in Java, it's free.
Notifo java client
a java client for Notifo
NotifoClient client = new NotifoHttpClient("username", "apikey");
// send yourself a message
client.sendMessage("here is my message");
// send someone a message
client.sendMessage("username", "here is my message");
// control all available aspects of the message
NotifoMessage message = new NotifoMessage("username", "message body");
message.setSubject("custom subject");
message.setLabel("custom label");
message.setUrl("custom url");
client.sendMessage(message);
for the non-maven types, here are the required dependencies