Question

I have a map between string and a class object. I populate this map in Activity1 and i would like to pass it to activity2.

public class NEW extends Activity {

    public class data {
            String name;
            float value;
                 ....   etc  }

 ......   
    static Map<String, data> data_map = new HashMap<String, data>();
   .....  }

Answer 1

I am assuming you own both Activities (call them A and B). In which case just put the map in a public static variable and access it from B via A.data_map.

[update]

For all of the downvotes take a peek at the Android Application Framework FAQ section “How do I pass data between Activities/Services within a single application?”. The solution I recommend is exactly the same as…

A public static field/method

An alternate way to make data
accessible across Activities/Services
is to use public static fields and/or
methods. You can access these static
fields from any other class in your
application. To share an object, the
activity which creates your object
sets a static field to point to this
object and any other activity that
wants to use this object just accesses
this static field.

Yes, there are caveats to this solution but with the limited info presented by the OP we can not assume this method will not work.