Java Technology Stack Interview Guide: Answers to Frequently Asked Questions

In the Java technology stack interview, common required questions involve multi-threading, collection framework, generics, JDBC and Spring framework. Mastering these questions can improve your interview success rate and understanding of Java technology. This article provides practical cases, covering: 1. Creating thread-safe counters; 2. Using collections to store and retrieve data; 3. Creating universal queues; 4. Using JDBC to connect to MySQL database; 5. Using Spring IoC for dependency injection.

Java Technology Stack Interview Guide: Answers to Frequently Asked Questions

In the Java technology stack interview, some questions are almost mandatory Taking the exam, mastering these questions will not only increase your interview pass rate, but also deepen your understanding of Java technology. This article will comprehensively answer common must-take questions from basic concepts to practical applications, and is equipped with practical cases to help you easily cope with interviews.

1. Java Multithreading

• #Question: What is multithreading and its main advantages and disadvantages?
• Code practice: Create a thread-safe counter:

public class ThreadSafeCounter {
    private int count = 0;
    private Object lock = new Object();

    public int increment() {
        synchronized (lock) {
            count++;
            return count;
        }
    }
}

2. Collection framework

• Question: What are the main collection types in Java Collections Framework? Briefly describe each type.
• Code practice: Use ArrayList and HashMap to store and retrieve data:

List<String> names = new ArrayList<>();
names.add("John");
names.add("Jane");
System.out.println(names.get(0)); // John

Map<Integer, String> ages = new HashMap<>();
ages.put(1, "20");
ages.put(2, "25");
System.out.println(ages.get(1)); // 20

3. Java Generics

• Question: What are non-generic classes and generic classes? Explain how type safety of generics is ensured.
• Code practice: Create a universal queue:

public class GenericQueue<T> {
    private List<T> elements = new ArrayList<>();

    public void enqueue(T item) {
        elements.add(item);
    }

    public T dequeue() {
        return elements.remove(0);
    }
}

4. JDBC

• Question: What is JDBC and how to use it to connect to a database?
• Code practice: Use JDBC to connect to the MySQL database:

Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM users");
while (rs.next()) {
    System.out.println(rs.getString("name"));
}

5. Spring Framework

• Question: What are the main modules in the Spring framework? Describe the functionality of each module.
• Code practice: Use Spring IoC to create a dependency injection Bean:

@SpringBootApplication
public class SpringBootApp {
    public static void main(String[] args) {
        SpringApplication.run(SpringBootApp.class, args);
    }

    @Bean
    public UserService userService() {
        return new UserServiceImpl();
    }
}

By mastering these common must-test questions and deepening it with practical cases By understanding, you can greatly improve your performance in Java technology stack interviews. Remember to express your answers clearly and provide specific examples to support your arguments.

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