Modular Development & Deployment Practices Flashcards

Which `module-info.java` directive allows a module to read another module's types without the consuming module explicitly requiring it?

Answer: requires transitive

`requires transitive` causes any module that requires the current module to also implicitly read the specified dependency.

A developer runs `java --list-modules`. What does this command display?

Answer: All observable system modules bundled with the JDK

`--list-modules` without additional arguments lists all observable system (platform) modules available in the running JDK.

Which tool is used to link a set of modules into a custom runtime image in Java 11?

Answer: jlink

`jlink` assembles and optimizes a set of modules and their transitive dependencies into a custom, self-contained runtime image.

What happens when you place a modular JAR on the class path instead of the module path?

Answer: The module-info.class is ignored and the JAR is treated as unnamed module content

When a modular JAR is placed on the class path, `module-info.class` is ignored and its classes become part of the unnamed module.

Which command-line option allows code in an unnamed module to access a specific package in a named module at runtime?

Answer: --add-exports

`--add-exports` makes a package in a named module accessible to another module (or unnamed module) without modifying `module-info.java`.

In a `module-info.java`, what is the purpose of the `uses` directive?

Answer: It declares that the module consumes a service via ServiceLoader

The `uses` directive specifies a service interface that this module may look up at runtime using `ServiceLoader`.

Which `jdeps` flag generates a `module-info.java` template for a non-modular JAR?

Answer: --generate-module-info

`jdeps --generate-module-info ` analyzes dependencies and writes a draft `module-info.java` to the specified directory.