1Z0-819 Modular Development & Deployment Practices 5

Question 1

Which `jlink` plugin reduces the size of the runtime image by removing debug information from class files?

Accepted Answer

--strip-debug

Answer

`--strip-debug` removes debugging information (such as variable names and line numbers) from class files to reduce image size.

Question 2

A named module `com.util` exports `com.util.api` but not `com.util.internal`. A class in `com.util.internal` is needed by a test on the class path. Which option allows reflective access without modifying module-info.java?

Accepted Answer

--add-opens com.util/com.util.internal=ALL-UNNAMED

Answer

`--add-opens` grants deep reflective access (private members included) to a package; `ALL-UNNAMED` targets code on the class path (the unnamed module).

Question 3

What does `jdeps --check <module-name>` report?

Accepted Answer

Unused exports and requires in the module's descriptor

Answer

`jdeps --check` compares the module's declared dependencies against its actual usage and reports unused `requires` or missing ones.

Question 4

When using `--module-path` and `--class-path` together, how does the JVM resolve type conflicts where the same class exists on both?

Accepted Answer

Named modules on the module path take precedence over the unnamed module (class path)

Answer

Named modules on the module path shadow any class with the same name on the class path, because named module types are never loaded by the unnamed module's class path.

Question 5

Which statement correctly describes an `open module` declaration?

Accepted Answer

The module allows deep reflection on all its packages at runtime but exports none publicly unless explicitly stated

Answer

An `open module` grants reflective access to all packages at runtime (equivalent to `opens` on each package) but does not change compile-time export visibility.

(1Z0-819) Oracle Java SE 11 Developer Practice Test

(1Z0-819) Oracle Java SE 11 Developer Practice Test

1Z0-819 Modular Development & Deployment Practices 5