Ch10 Modules

Question 1

Given a module ‘zoo.animal.feeding’ with a file Task.java, in the root directory ‘test’ and a directory ‘mods’ containing custom module files.

Compile the code.

Answer 1

javac -p mods test/zoo/animal/feeding/Task.java test/module-info.java

or

javac –module-path mods test/zoo/animal/feeding/Task.java test/module-info.java

Question 2

Suppose there is a module named book.module which was compiled in the directory ‘test’. Inside that module is a package named com.sybex, which has a class named OCP with a main() method.

Using the above information, run the module.

Answer 2

java –module-path test –module book.module/com.sybex.OCP

–module-path can be replaced by -p and –module can be replaced by -m

Question 3

Package everything under the ‘test’ directory to the mods directory under the name zoo.animal.feeding

Answer 3

jar -cvf mods/zoo.animal.feeding.jar -C test/ .

Question 4

What command can we use to find out what the module structure is of a jar file?

Answer 4

java -p {module-path here} -d {module here}

or

java -p {module-path here} –describe-module {module here}

Question 5

What command can we use to list available modules?

Answer 5

java –list-modules
/
java -p mods –list-modules

Question 6

What flag can we use to print debugging information when running the modules?

Answer 6

–show-module-resolution

Question 7

What command can we use to get information about dependencies within a module that are actually used (and not just declared)?

Answer 7

The jdeps command

Question 8

Use a command to get information about actual dependencies of the module zoo.staff in the directory mods.

Answer 8

jdeps mods/zoo.staff.jar

Question 9

Use a command to get a summary of the information about actual dependencies of the module zoo.staff in the directory mods.

Answer 9

jdeps -s mods/zoo.staff.jar

or

jdeps -summary mods/zoo.staff.jar

Question 10

Name all important JMOD operations

Answer 10

create, extract, describe, list, hash