Engineering Admission Process

No! Lateral entry is the admission process for diploma holder students for admission directly in the second year. You have to give an entrance exam.

I am not sure that JMI provides lateral entry for B.Tech courses or BE because there is nothing given about it on their website.

No, but if you are interested in IIT's then go for it.
Don't consider one year as waste it doesn't matter before your career.
If you get selected, you will have a bright future.

If you are enquiring about the entrance exam, it's based on your Diploma topics and concepts where they will examine your conceptual and applications skills.
So, be sure on the basics of technical concepts.
Otherwise, if you are enquiring about B.Tech syllabus, it is same as of general students who joined B.Tech after their 12th.

Yes, there is a seat available in Civil engineering in DTU.
For which you have to appear for the entrance exam for DTU LEET.
For more information,
Visit this site
http://www.dtu.ac.in/Web/Admission/b.tech(LE).php

The list of colleges in Kerala offering B.Tech through lateral entry is given below;
KMEA Engineering College
Vidya Academy of Science & Technology
Government Engineering College, Thirussur
AWH Engineering College
Government Model Engineering College
MS College of Engineering and Technology
Sree Narayana Guru Memorial Educational Campus
Calicut University Institute of Engineering and Technology
Regards.

Hello
In VIT-Pune, there is no lateral entry for MCA course unlike in engineering courses.
All the best!