这是我得到的错误：

Exception in thread "main" java.lang.Error: Unresolved compilation problem:  
    TeamLeader cannot be resolved to a type

    at TeamLeadDemo.main(TeamLeadDemo.java:26)

这是我的代码：

import java.util.Scanner;

public class Employee {
    public String empName, empNumber, hireDate;    

    public class TeamLeadDemo {}

    public Employee(String empName, String empNumber, String hireDate) {
        this.setEmpName(empName);
        this.setEmpNumber(empNumber);
        this.setHireDate(hireDate);
    }

    public void setEmpName(String empName) {
         this.empName = empName;
    }
        public void setEmpNumber(String empNumber) {
         this.empNumber = empNumber;
    }
    public void setHireDate(String hireDate) {
         this.hireDate = hireDate;
    }
    public String getEmpName() {
        return empName;
    }
    public String getEmpNumber() {
        return empNumber;
    }
    public String getHireDate() {
        return hireDate;
    }

    public class ShiftSupervisor extends Employee {
        public double annualSalary, annualProduction;
        //constructor
        public ShiftSupervisor(String empName, String empNumber,
                               String hireDate, double annualSalary,
                               double annualProduction) {
            super(empName,empNumber, hireDate);
            this.setAnnualSalary(annualSalary);
            this.setAnnualProduction(annualProduction);
        }

        public double getAnnualSalary() {
            return annualSalary;
        }
        public double getAnnualProduction() {
            return annualProduction;
        }
        public void setAnnualSalary(double annualSalary) {
            this.annualSalary = annualSalary;
        }
        public void setAnnualProduction(double annualProduction) {
            this.annualProduction = annualProduction;
        }

        public String toString() {
            return "Name: "+ getEmpName() + "\nEmpID: "+ getEmpNumber()
                   + "\nHire Date: "+ getHireDate() + "\nAnnual Salary: "
                   + annualSalary + "\nProduction: "+ annualProduction;
        }

        public class employeeStart {
            public void main(String[] args) {
                String name, id, date;
                double sal, prod;

                //create scanner object
                Scanner keyboard = new Scanner(System.in);

                //inputting data
                System.out.println("Enter Name: ");
                name = keyboard.nextLine();
                System.out.println("Enter id: ");
                id = keyboard.nextLine();
                System.out.println("Enter Hire Date: ");
                date = keyboard.nextLine();
                System.out.println("Enter Annual: ");
                sal = keyboard.nextDouble();
                System.out.println("Enter production: ");
                prod = keyboard.nextDouble();

                //instantiating object
                ShiftSupervisor pw = new ShiftSupervisor(name, id, date, sal, prod);

                //outputting data
                System.out.println("Employee Details: \n" + pw);
            }
        }
        public class TeamLeader {
            public double monthlyBonus;
            public int minTraining, trainingPresent;    

            public TeamLeader(double monthlyBonus, int minTraining, int trainingPresent) {
                this.setMonthlyBonus(monthlyBonus);
                this.setMinTraining(minTraining);
                this.addtrainingPresent(trainingPresent);                    
            }

            public void setMonthlyBonus(double monthlyBonus) {
                this.monthlyBonus = monthlyBonus;
            }
            public void setMinTraining(int minTraining) {
                this.minTraining = minTraining;
            }
            public void setTrainingPresent(int t) {
                trainingPresent = t;
            }
            public void addtrainingPresent(int hours) {
                trainingPresent += hours;
            }
            public double getMonthlyBonus() {
                return monthlyBonus;
            }
            public int getMinTraining() {
                return minTraining;
            }
            public int getTrainingPresent() {
                return trainingPresent;
            }
            public String toString() {
                return "Bonus: "+ getMonthlyBonus() + "\nMinimum Training: "
                + getMinTraining() + "\nAttendence: "+ getTrainingPresent();
            }
        }
    }
}

此外，我在一个单独的类中声明了这一点：

import java.util.Scanner;

public class TeamLeadDemo extends Employee {
    public TeamLeadDemo(String empName, String empNumber, String hireDate) {
        super(empName, empNumber, hireDate);
        // TODO Auto-generated constructor stub
    }

public static void main(String[] args) {
    double sal;
    int min, atten;

    //create scanner object
    Scanner keyboard = new Scanner(System.in);

    //inputting data
    System.out.println("Enter minimum training: ");
    min = keyboard.nextInt();
    System.out.println("Enter id: ");
    atten = keyboard.nextInt();
    System.out.println("Enter Bonus: ");
    sal = keyboard.nextDouble();

    //instantiating object
    ShiftSupervisor pw = new TeamLeader(sal, min, atten);

    //outputting data
    System.out.println("Employee Details:\n" + pw);

    }
}

导致此错误的原因是什么？我应该如何解决它？
编辑：缩进、空格、命名约定和可读性问题已经得到了一定程度的解决。