Tips on removing nesting

CleanNests.java

import java.util.Arrays;
import java.util.List;

//PART OF Clean Code series //https://medium.com/@ankushchoubey/series-tips-on-writing-clean-code-30d717f32ae4
class Student { // POJO 🤘
  String name;
  List<Integer> grades;
  // skipping getter/setter:
  // tip: google "project lombok"
}

class BadGrader { // Line of Code: 9, Indentation: 2
  void printAllAverageGrades(List<Student> students) {
    for (Student student : students) {
      int count = 0; // the logic of calculating grade is embedded within the loop
      float sum = 0;
      for (Integer grade : student.grades) {
        sum += grade;
        count+=1;
      }
      System.out.println("Name: " + student.name + "\Avg Grade:" + sum / count);
    }
  }
}

class BetterGrader { // Line of Code: 10, Indentation: 2
  float calculateAverageGrade(List<Integer> grades) {
    // now we can use our same grading logic else where.
    int count = 0;
    float sum = 0;
    for (Integer grade : grades) {
      sum += grade;
      count+=1;
    }
    return sum / count;
  }

  void printAllAverageGrades(List<Student> students) {
    for (Student student : students) {
      System.out.println("Name: " + student.name + "\tAvg Grade:" + calculateAverageGrade(student.grades));
    }
  }
}

class GoodGrader {//Line of code 2: 
  double calculateAverageGrade(List<Integer> grades) {
    // Using streams
    // https://stackoverflow.com/questions/48906552/using-java-stream-to-get-a-sum-average-and-sort#48906784
    return grades.stream().mapToInt(Integer::intValue).average().getAsDouble();
  }

  void printAllAverageGrades(List<Student> students) {
    students.forEach(student -> System.out.println("Name: " + student.name + "\tAvg Grade:" + calculateAverageGrade(student.grades));
  }
}

class GoodShorterGrader {//Line of code 2: 
  double getAvgGrade(List<Integer> grades) {
    // Using streams
    // https://stackoverflow.com/questions/48906552/using-java-stream-to-get-a-sum-average-and-sort#48906784
    return grades.stream().mapToInt(Integer::intValue).average().getAsDouble();
  }

  void printAllAverageGrades(List<Student> students) {
    students.forEach(student -> System.out.println("Name: " + student.name + "\tAvg Grade:" + getAvgGrade(student.grades));
  }
}

class CleanNests {
  public static void main(String[] args) {
    Student a = new Student();
    Student b = new Student();
    a.name = "A";
    a.grades = Arrays.asList(1, 2, 3, 4);

    b.name = "B";
    b.grades = Arrays.asList(6, 7, 4, 4);

    List<Student> students = Arrays.asList(a, b);

    System.out.println("BadGrader");
    BadGrader bg = new BadGrader();
    bg.printAllAverageGrades(students);

    System.out.println("BetterGrader");
    BetterGrader beg = new BetterGrader();
    beg.printAllAverageGrades(students);

    System.out.println("GoodGrader");
    GoodGrader gg = new GoodGrader();
    gg.printAllAverageGrades(students);

    System.out.println("GoodShorterGrader");
    GoodShorterGrader gsg = new GoodShorterGrader();
    gsg.printAllAverageGrades(students);
  }
}