在Kotlin中引用和使用Java对象，上下文为

// Java类
public class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

// Kotlin代码
fun main() {
    val person = Person("Alice", 30)
    println("Name: ${person.name}, Age: ${person.age}")
}

val name: String = person.name // 如果person.name为null，会抛出异常

val name: String? = person.name // 使用可空类型
if (name != null) {
    println("Name: $name")
}

val ages: List<Int> = person.getAges() // 假设getAges()返回的是List<Integer>

val ages: List<Int> = person.getAges().map { it.toInt() }

// 为Java的Person类添加一个扩展函数
fun Person.greet(): String {
    return "Hello, my name is ${this.name} and I am ${this.age} years old."
}

fun main() {
    val person = Person("Bob", 25)
    println(person.greet())
}