Happy to say that I've passed the Java SE 8 Programmer I exam with 88%. Now I can say I'm "certified" It took me about 3 months for prepping in the middle of my busy routines (Weekends were a delight), And 1 whole month for mocks and to narrow down areas where I'm less familiar with. Thanks to fellow coderanchers whose discussions clarified my doubts. And thanks to "valar" who kept pushing me when I was down and thought I couldn't do this.
Books I've used:
1. OCAOCP Java SE 7 Programmer I & II Study Guide (Exams 1Z0-803 & 1Z0-804) By Kathy Sierra & Bert Bates.
I would say this book has more detailing to it than Jeanne & Scott. For takers, if you have more time I would suggest you go with this. It gave me clearer understanding but due to short in time I switched to Jeanne.
2. OCA: Oracle Certified Associate Java SE 8 Programmer I Study Guide: Exam 1Z0-808 -Jeanne Boyarsky, Scott Selikoff : For the parts that were newly included in 1Z0-808