1Z0-819 Modules System 3

Question 1

Which JDK tool creates a custom runtime image from a set of modules?

Accepted Answer

jlink

Answer

'jlink' assembles and optimizes a custom runtime image containing only the specified modules and their transitive dependencies.

Question 2

What does the 'jdeps' tool primarily do in the context of the module system?

Accepted Answer

Analyzes class files to determine module and package dependencies

Answer

'jdeps' analyzes class-file bytecode and reports module-level and package-level dependencies.

Question 3

What is the unnamed module in Java's module system?

Accepted Answer

A special module that contains all classes loaded from the classpath

Answer

The unnamed module is a catch-all module that contains all types loaded from the classpath, enabling backward compatibility.

Question 4

Which JVM option allows deep reflection from one named module into a package of another module at runtime without modifying source?

Accepted Answer

--add-opens

Answer

'--add-opens module/package=targetModule' grants reflective access similar to an 'opens' directive without modifying module-info.

Question 5

A module-info.java contains 'exports com.example.util to com.app.core;'. This means:

Accepted Answer

Only com.app.core can access the public types in com.example.util

Answer

A qualified export restricts access to the exported package's public types to only the specified module(s).

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