JRebel is a build automation tool developed by Estonian company ZeroTurnaround, acquired by Rogue Wave Software in 2017, and then acquired (and now supported by) Perforce since that company's 2019 acquisition of Rogue Wave. The vendor says users of JRebel saves Java teams a month of coding time per year on average.
Hot code swapping doesn't have many players...it's mainly JRebel. We use JRebel a lot in our backend code development where it minimizes our development cycle (20min down to 30sec). For Android, the competitor is Android Studio's Instant Run which works fairly well now. For …
I recommend JRebel for Java developers, it will remove the time needed for redeployment, it will increase the focus on the task at hand (without being distracted by the redeployment) and will make them happier. I recommend JRebel for Java Development Managers, they should purchase this for their teams - it will increase productivity, decrease the product's time to market, and it will save money for the company. The ROI can be calculated upfront and presented to higher level management for approving this, if needed.
Deploys all layout changes consistently (when Instant Run was initially available, you couldn't tell if the change you made to a layout was actually being tested or not).
Doesn't require a full build as often as Instant Run when changing code.
Works with compile time annotation libraries like Realm, etc.
The performance of JRebel is great. It is enabling the Java team to do hot re-deployments and it has to be transparent and fast for the user, otherwise the whole purpose of reducing wasted time with re-deployments doesn't make sense. Also the User Interface for License Server management and analytics loads fast and the navigation through pages is quick.
Hot code swapping doesn't have many players...it's mainly JRebel. We use JRebel a lot in our backend code development where it minimizes our development cycle (20min down to 30sec). For Android, the competitor is Android Studio's Instant Run which works fairly well now. For smaller apps, Instant Run is faster deploying but needs more full builds. With JRebel, you hardly ever need to do a full build.