hi I'm a fresh newbie to mongodb

Q1 using query=new BasicDBObject(); query.put("i", new BasicDBObject("$gt",13)); and query=new QueryBuilder().put("i").Greaterthan(13).get()

is there any difference inside of the system?

Q2 I've created a class

        class findkv extends BasicDBObject{ 
    //is gt gte lt lte  
  public findkv(String fieldname,String op,Object tvalue)
        {
            if (op=="")
                this.put(fieldname,tvalue);
                else 
                    this.put(fieldname, new BasicDBObject(op,tvalue));
        }

    }

shall I use it or shall I just use original function?

Q3 I've used mongo shell for a few weeks, and was customed to it, and find writing in mongo shell faster and shorter, which side has more advantage, writing in mongo or in java?

I shall dump them from mongo to mysql

Q4

I've an if (statement==true) return else dowhat; seems can't be compiled I know I can write if (statement!=true) dowhat else return, but can I still write in first style?

q5 my eclipse is Eclipse Java EE IDE for Web Developers.

Version: Juno Release Build id: 20120614-1722 I'd like to install Perl which I haven't learned yet I choose Install Update http://e-p-i-c.sf.net/updates/testing but it doesn't work, any method to install perl to eclipse manually?