working with 2 log files and output into 3rd log file

I was given task that I need to take 2 log files in which the content is just like database where in 1 file I have attributes like id,name,address and in other file I have attributes like id,name,Email,contactnumber and corresponding values for those attributes seperated by commas in both files.The output should be in 3rd log file where the attributes should be id,name,address,Email,contactnumber and corresponding values.I am a fresher in java.so I was unable to find solution for this problem.Thanks in advance.