How to read the .xls file and write it back accordingly using groovy?

I am stuck badly at one place. I need to read an .xls file using groovy/java and then write it back to another sheet. I have attached the sheet with this question. If you open the excel sheet. You will see 2 sheet's 

1. InputRead - Which I want to read using groovy/java

2. OutputWrite - Where I will be writing the data.

You can see the format, I want to write it to. The values inside column ID and Date may vary (Its dynamic). 

Please help me on this. Need help.

Thanks in advance.