1Z0-811 Java Development and Deployment 4

Question 1

Which `jar` command option lists the contents of an existing JAR file?

Accepted Answer

jar --list --file app.jar

Answer

`jar --list` (or `jar -tf`) lists all entries in the specified JAR archive.

Question 2

When module-info.java contains `uses com.example.Printer;`, what does this indicate?

Accepted Answer

The module is a consumer of the Printer service via ServiceLoader

Answer

The `uses` directive registers the module as a consumer of a service type, allowing `ServiceLoader` to discover implementations at runtime.

Question 3

Which Java 11 feature allows running a single-file source program without explicitly compiling it first?

Accepted Answer

java Hello.java

Answer

Java 11 added the ability to launch single-file source-code programs directly with `java SourceFile.java`, which compiles in memory.

Question 4

What does the `--show-module-resolution` JVM flag output during startup?

Accepted Answer

A trace of which modules are being resolved and in what order

Answer

`--show-module-resolution` prints resolution steps at startup, useful for diagnosing module graph problems.

Question 5

Which directory inside a module source tree conventionally holds the `module-info.java` file?

Accepted Answer

The root of the module's source directory

Answer

`module-info.java` is placed at the root of the module's source tree, at the same level as the top-level package directories.

(1Z0-811) Oracle Java SE11 Programmer Practice Test