public class Employee {
    private String Email;
    
    public String getEmail() {
        return Email;
    }

    public void setEmail(String Email) {
        this.Email = Email;
    }

    /**
     * You've to Override `equals` and `hashCode` methods in order to work `distinct` method of `stream`.
     */
    @Override
    public boolean equals(Object obj) {
        Employee compareEmployee = (Employee) obj;
        if(this.Email != null && compareEmployee != null){
            return this.Email.equalsIgnoreCase(compareEmployee.getEmail());
        }else{
            return false;
        }
    }

    @Override
    public int hashCode() {
        if(this.Email != null && !this.Email.trim().isEmpty()){
            return this.Email.hashCode();
        }else{
            return -1;
        }
    }    
}

import java.util.ArrayList;
import java.util.List;

public class DistinctExample {
    public static void main(String[] args) {
        /* Create `List` of `String` and add duplicate records */
        List<String> listStrings = new ArrayList<>(0);
        listStrings.add("Chirag");
        listStrings.add("Vicky");
        listStrings.add("Vicky");
        
        System.out.println("Distinct Strings in `listStrings`: ");
        listStrings.stream()
                   .distinct()
                   .forEach(strName -> {
                       System.out.println("> " + strName);
                   });
        
        /* Create `List` of `Long` and add duplicate records */
        List<Long> listNumbers = new ArrayList<>(0);
        listNumbers.add(22L);
        listNumbers.add(22L);
        listNumbers.add(11L);
        
        System.out.println("Distinct Numbers in `listNumbers`: ");
        listNumbers.stream()
                   .distinct()
                   .forEach(number -> {
                       System.out.println("> " + number);
                   });
        
        /**
         * Create `List` of `Employee` and add duplicate records
         * Note: In case of Bean or Pojo you've to Override `equals` and `hashCode` methods in Bean or Pojo
         */
        List<Employee> listEmployee = new ArrayList<>(0);
        Employee employeeChirag = new Employee();
        employeeChirag.setEmail("chirag.thakor@javaquery.com");
        listEmployee.add(employeeChirag);
        
        Employee employeeVicky = new Employee();
        employeeVicky.setEmail("vicky.thakor@javaquery.com");
        listEmployee.add(employeeVicky);
        
        Employee employeeDuplicate = new Employee();
        employeeDuplicate.setEmail("vicky.thakor@javaquery.com");
        listEmployee.add(employeeDuplicate); 
        
        System.out.println("Distinct Employee in `listEmployee`: ");
        listEmployee.stream()
                    .distinct()
                    .forEach(employee -> {
                       System.out.println("> " + employee.getEmail());
                    });
    }
}

Distinct Strings in `listStrings`: 
> Chirag
> Vicky
Distinct Numbers in `listNumbers`: 
> 22
> 11
Distinct Employee in `listEmployee`: 
> chirag.thakor@javaquery.com
> vicky.thakor@javaquery.com