A_bday_java

Working with the Java Launcher

Project Structure

Here's a breakdown of the different project components:

• src/main/java: The source code for the project, organized by package:
  • eu.ammbra.bday.Organizer.java: The main entry point of the application, possibly responsible for coordinating the overall flow of the program.
  • eu.ammbra.bday.details: A package containing domain model classes. These classes represent entities involved in birthday celebrations, such as cakes, parties, and people attending them.
  • eu.ammbra.bday.handlers: A package containing classes responsible for handling specific tasks.
  • eu.ammbra.bday.operations: A package containing classes responsible for handling the operational side of parties.
  • eu.ammbra.bday.store: A package containing classes responsible for interacting with data from files.
• src/main/resources/store/events.json: A resource file containing sample event data in JSON format.
• src/test/java: The source code for unit tests and integration tests.

Lab Activity No 1: Launch Multiple Java Files

Since JDK 22 you can use the Java launcher to execute source-code programs provided as multiple files.

java --class-path '*' Prog1.java

This activity relies on you to execute the following steps:

1. Open a terminal window in the lab-jdk-tools/A_bday_java folder. You can use the terminal of your IDE/code editor.
2. Check that $JAVA_HOME is properly set by trying echo $JAVA_HOME.
3. Inside the terminal, execute the java command to launch Organizer class from src/main/java/eu/ammbra/bday/. Pay attention to the following:

• classpath libraries located in lab-jdk-tools/lib folder.
• the project uses preview features so do not forget to enable those via --enable-preview

Solution

→ Click to see the solution

Lab Activity No 2: Use the Java Command-Line Argument Files

When working with the java launcher, you can shorten or simplify the java command by using @ argument files to specify one or more text files that contain arguments. The arguments can be options and class names, which are then passed to the java command. This allows you to :

• create java commands of any length on any operating system
• for containerized applications, easily swap the content the argument files without modifying the Dockerfile.

This activity requires you to:

1. Create a file and copy the arguments you used to launch the Organizer class from src/main/java/eu/ammbra/bday/.
2. Now launch again the Organizer class by providing the file as argument java @your-arg-file-name.

Solution

→ Click to see the solution

Next step is to create some documentation!