• Due to the requirement for diff steps of practice which in README.md of test folder, Please write the corresponding implementation code in src folder to pass tests and fulfill the requirement.

1. Java Syntax implementation for the different feature in OO
2. Three main feature in OOP.
3. Read and run tests to understand the implementation validation and business logic.
4. Use a design program with basic OO Thinking.
5. How to Use Observer Pattern to decouple the two-way dependencies.

• Java 8
• Intellij-IDEA
• Gradle (Optional)

Use below command to clone practice to your local machine

git clone repo_of_this_template

Run tests command：

./gradlew test
or
gradle test (if you have Gradle installed in local machine)

• Due to the requirement in src/test/java/paractice_/README.md, Complete the corrsponding code in src/main/java/practice_/。Test must be passed, requirement must be fulfilled.
• Before coding you should uncomment the test methods in test class.
• Understand what happens during the execution of the code. If you can't understand it, use the debugger to step through it to aid understanding.
• git commit with meanful comments after each test method is passed。

• You should implement the code to pass all tests in test folder after uncomment all test methods, and push your repo to github repo named java-oo-stey-by-step.
• Commit your repostory link to complete this Question.