JRE
ExplainedPlatform
Also known as: Java Runtime Environment
The runtime for executing compiled Java programs (JVM plus standard libraries).
JRE, explained
Written by EduVerseWhat it is
The JRE (Java Runtime Environment) is what a machine needs to run a Java program that has already been compiled. It bundles the JVM with Java’s standard class libraries, but leaves out the compiler and development tools that come with the JDK.
Why teams use it
A server that only runs your application has no use for a compiler. A runtime on its own is smaller and gives an attacker fewer tools to work with. Oracle no longer offers a separate JRE download for recent Java versions, so teams use a JRE build from another vendor, such as Eclipse Temurin, or create a trimmed runtime with jlink.
An example from work
You open a Dockerfile with two stages: the first starts FROM a JDK image and runs the Maven build, the second starts FROM a JRE image and only copies in the finished .jar. The final image is smaller because the compiler and build tools stay behind in the first stage.
Our own explanation, not a quote from the book.
Where it fits
Running Java applications without the full JDK
Coverage in the book
Explained and compared with alternatives, so you know where and why it’s used.
