How can I do this with programming?

1)Read all files from a folder in the same directory

2)Files with the same name but different extension

3)On .txt extensions,count the number of words,the start and end offset of each word,output into a textfiles

4)Merge a1,a2,ann,rel(other file extensions),on read each line,and store it into a data-structure

5)Join results of 3,4 and output into a new folder <previousfolder>_result

I am preferred to use java to do this?