Final Conclusion and Quick Revision.....

To summarise:

Continuous Integration (CI), short feature branches, team is merging to master or central branch multiple times a day, fully automated build and test process with manual deployment.

Continuous Delivery (CD), CI+ Automated software release + Manual Deployment to production with manual approvals.

Continuous Deployment (CD), CI+ CD + fully automated deployment to production without manual approval.

Tool Used: Maven (Build tool), Gradle (Build tool, preffered for andriod), Jenkins (most preffered).