Polymorphic application: template method design pattern (TemplateMethod)

public class TemplateTest {
    
    
    public static void main(String[] args) {
    
    
        SubTemplate t = new SubTemplate();
        t.spendTime();
    }
}

abstract class Template {
    
    
    public void spendTime() {
    
    
        long start = System.currentTimeMillis();
        code();
        long end = System.currentTimeMillis();
        System.out.println("spend time:" + (end - start));
    }

    public abstract void code();
}

class SubTemplate extends Template {
    
    
    @Override
    public void code() {
    
    
        System.out.println("code");
    }
}