Q:

Convert easting and northing to latitude longitude cordinates

I have some easting and northing coordinates .. and I want to convert this coordinates to latitude longitude.. using java or android libraries.
any suggestions please

A:

That is basically the reverse of projection. You need to know what projection your Eastings and Northings are in before you can do anything. Then you can apply the converse of the projection transformation to get Latitudes and Longitudes on a datum. You can either find the transformation (usually a fairly straightforward mathematical function, see the wikipedia link above) and implement it yourself, or use a 3rd-party library such as Geotools or GeoAPI.
See also these two useful pages about the often-used Spherical Mercator:
Spherical Mercator and Google Maps Tiles (Spherical Mercator section)

