how to make all the Empty cells as a blank cells

Please find the attached excel for understanding

Lets consider only the first 3 rows on the attached excel

I am reading the excel from a java file. so that the cells F2,G2,A3,B3 and E3 are taken as empty by which it is returning as "null". But for me it should taken as "".

this can be achieved by, writing some texts in the cells F2,G2,A3,B3 and E3 and deleting the values (texts).

This can be possible for 3 or 4 rows.. But how to make it possible for the whole sheet. Any idea..??

So that none of the empty cells should return as "null" but rather it should return as "" (blank values)..

Plz help.. Its very critical and have to fix it..