An Introduction to Hollow JARs - DZone Java

An Introduction to Hollow JARs - DZone Java

The main benefit comes from the fact that the JAR component of the Hollow JAR deployment pair won't change all that frequently. While you could expect to deploy new versions of the WAR half of the deployment multiple times per day, the JAR half will remain static for weeks or months. This is particularly useful when building up layered container images, as only the modified WAR file needs to be added as a container image layer.

Likewise, you may also reduce build times with technologies like AWS autoscaling groups. Because the JAR file doesn't change often, this can be baked into an AMI, while the WAR file can be downloaded as an EC2 instance is deployed through the scripting placed into an EC2 user data field.

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