Java 中的泛型是什么 [关闭]

Java中的泛型是什么?

java
public class Box {
    private T content;
    public void setContent(T content) {
        this.content = content;
    }
    public T getContent() {
        return content;
    }
}
public class Main {
    public static void main(String[] args) {
        Box stringBox = new Box<>();
        stringBox.setContent("Hello, World!");
        System.out.println(stringBox.getContent());
        Box intBox = new Box<>();
        intBox.setContent(42);
        System.out.println(intBox.getContent());
    }
}