[Turtle]

Read the comments in this code.
And refer to the online documentation: Java Platform SE 6
Also, check out the networking tutorials: Trail: Custom Networking (The Java™ Tutorials)

Code:

// Imports must be preceded with the keyword import.
// Each import must be terminated with a semi-colin (as with all statements).
// Note, you can import all classes from a package by using an astriks...
// import java.io.*;
// This is not recursive though, classes in sub-packages with need to be imported too.

// import java.io.ObjectOutputStream;
// import java.io.ByteArrayOutputStream;
import java.io.*;

// Required for DatagramSocket, InetAddress & DatagramPacket
// As these classes reside in this package...
import java.net.*;

class Test {

// The getBytes method throws an UnsupportedEncodingException exception, you may want to handle this if it is dynamically set.
	public static void main(String args[]) throws UnsupportedEncodingException {
		//creates a string for name called Help
		// Java is case sensitive, I've changed this to a capital S.
		// Also, each statement must be terminated with a semi-colin.
		String S = "Help";
		
		//Converts name into byte sequence
		byte[] B = S.getBytes("US-ASCII");	// getBytes is a instance method and must be used on an instance of an object.

		// Converting int to String...
		// The value range an integer can hold is -2^31 to 2^31-1
		// That's from -2,147,483,648 to 2,147,483,647
		// The max & min numbers can be found in a primative classes wrapper class...
		// http://java.sun.com/javase/6/docs/api/java/lang/Integer.html
		// Your number is within the range of a double, but for even larger numbers check out the BigInteger class.
		int intNumber = 50;	
		String stringNumber = String.valueOf(intNumber);
		
		//Convert number into byte sequence
		B = stringNumber.getBytes("US-ASCII");	// getBytes is a instance method and must be used on an instance of an object.

		//create datagram socket
		DatagramSocket aSocket;
		try {
			aSocket = new DatagramSocket();	// Needed to declare the variable type
		} catch (SocketException se) {
			System.out.println("DataSocket can and has thrown a SocketException. Exiting application");
			return;
		}
		//Host name
		InetAddress address;
		try {
			address = InetAddress.getByName("localhost");	// Missed a semi-colin
		} catch (UnknownHostException uhe) {
			System.out.println("InetAddress can and has thrown a UnknownHostException. Exiting application");
			return;
		}
		
		//set port number
		//public function set ServerPort (3670 : int)
		int serverPort = 3670;
		
		//create datagram packet
		// m is the packet data, and should be assigned - I have switched it with B
		// The packet length should get the length from the data (B.length) it is sending.
		// I am assuming your host is the "address".
		DatagramPacket request = new DatagramPacket(B, B.length, address, serverPort);

		// Send it
		try {
			aSocket.send(request);
		} catch(IOException ioe) {
			System.out.println("The send method can and has thrown an IOException. Exiting application");
			return;
		}
	}
}