Download redstone xml rpc from source forge:

http://sourceforge.net/projects/xmlrpc/files/%28New%29%20Redstone/

Set classpath to include the jar file.

Enable rpc at  http://<wordpress site>/wp-admin/options-writing.php

compile and run the following code:

import redstone.xmlrpc.XmlRpcClient;
import java.util.HashMap;

public class XmlRpcPoster
{
  public static void main( String[] args )
  {
    // Check command-line arguments
    if( args.length < 3 )
    {
      System.out.println( "Usage: java XmlRpcPoster <XML-RPC URL Entry Point> <username> <password>" );
    }
    else
    {
      // Get command-line arguments into variables
      String sXmlRpcURL = args[0];
      String sUsername = args[1];
      String sPassword = args[2];

      // Hard-coded blog_ID
      int blog_ID = 1;

      // XML-RPC method
      String sXmlRpcMethod = "metaWeblog.newPost";

      // We'll hard-code our blog content for now as well
      String sContent = "Hello XML-RPC World!";
      String sTitle = "Hello XML-RPC Title";

      // Create our content struct
      HashMap hmContent = new HashMap();
      hmContent.put("title", sTitle);
      hmContent.put("description", sContent);

      // You can specify whether or not you want the blog published immediately
      boolean bPublish = true;

      // Try block
      try
      {
        // Create the XML-RPC client
        XmlRpcClient client = new XmlRpcClient( sXmlRpcURL, false );

        // Make our method call
        Object token = client.invoke( sXmlRpcMethod, new Object[] { new Integer( blog_ID ), sUsername, sPassword, hmContent, new Boolean( bPublish ) } );

        // The return is a String containing the postID
        System.out.println( "Posted : " + token.toString() );
      }

      // Catch exceptions
      catch( Exception e )
      {
        e.printStackTrace( System.err );
      }
    }
  }
}