Unisex Bathroom Problem

import java.util.ArrayList;
import java.util.concurrent.Semaphore;

class Toilet{
    int semporeNum = 40;
    Semaphore s = new Semaphore(semporeNum);
    String MALE = "MALE";
    String FEMALE = "FEMALE";
    String NONE = "NONE";
    String occupiedBy = NONE;
    ArrayList<String> arrString = new ArrayList<>();
    public void enterMale(String name) throws InterruptedException {
        synchronized (this){
            /*If bathroom is full or occupied by female let person wait*/
            while(s.availablePermits()==0 || occupiedBy.equals(FEMALE)){
                wait();
            }
            s.acquire();
            occupiedBy = MALE;
        }

        doToilet(MALE + "_" + name);



        synchronized (this){
            showToilet();
            s.release();
            /*If bathroom is vacant set bathroom is vacant*/
            if(s.availablePermits()==semporeNum){
                occupiedBy = NONE;
            }
            notifyAll();
        }
    }

    public void enterFemale(String name) throws InterruptedException  {
        synchronized (this){
            /*If bathroom is full or occupied by male let person wait*/
            while(s.availablePermits()==0 || occupiedBy.equals(MALE)){
                wait();
            }
            s.acquire();
            occupiedBy = FEMALE;
        }


        doToilet(FEMALE + "_" + name);
        synchronized (this){
            showToilet();
            s.release();
            /*If bathroom is vacant set bathroom is vacant*/
            if(s.availablePermits()==semporeNum){
                occupiedBy = NONE;
            }
            notifyAll();
        }
    }

    public void doToilet(String candidate)  throws InterruptedException {
        /*taking lock on arrString because we are doing addition and substraction here*/
        synchronized (arrString) {
            System.out.println("Candidate " + candidate + "  Entered to do toilet ");
            arrString.add(candidate);
        }

        Thread.sleep(5);

        /*taking lock on arrString because we are doing addition and substraction here*/
        synchronized (arrString){
            arrString.removeIf(element -> element.equals(candidate));
            System.out.println("Candidate " + candidate + "  left from toilet ");
        }
    }

    public void showToilet(){
        /*taking lock on arrString because we are doing addition and substraction here*/
        synchronized (arrString) {
            System.out.println("\n-------------------------------------------------------\n");
            for(int i=0;i<arrString.size();i++){
                System.out.print( " " + arrString.get(i) + " ");
            }
            System.out.println("\n-------------------------------------------------------\n");
        }
    }
}


public class ToiletProblem {

    public static void main(String []args) throws Exception
    {
        String MALE = "MALE";
        String FEMALE = "FEMALE";
        String NONE = "NONE";
        String occupiedBy = NONE;

        Toilet toilet = new Toilet();

        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    for(int i=0;i<5;i++){
                        System.out.println("Trying to enter toilet " + "MALE" + i);
                        toilet.enterMale("MALE" + i);
//                        toilet.showToilet();
                    }
                }catch (InterruptedException ex){

                }
            }
        });

        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    for(int i=0;i<5;i++){
                        System.out.println("Trying to enter toilet " + " FEMALE " + i);
                        toilet.enterFemale("FEMALE" + i);
//                        toilet.showToilet();
                    }
                }catch (InterruptedException ex){

                }
            }
        });


        Thread t3 = new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    for(int i=51;i<56;i++){
                        System.out.println("Trying to enter toilet " + "MALE" + i);
                        toilet.enterMale("MALE" + i);
//                        toilet.showToilet();
                    }
                }catch (InterruptedException ex){

                }
            }
        });


        Thread t4 = new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    for(int i=51;i<56;i++){
                        System.out.println("Trying to enter toilet " + "FEMALE" + i);
                        toilet.enterFemale("FEMALE" + i);
//                        toilet.showToilet();
                    }
                }catch (InterruptedException ex){

                }
            }
        });


        Thread t5 = new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    for(int i=1000;i<1050;i++){
                        System.out.println("Trying to enter toilet " + "MALE" + i);
                        toilet.enterMale("MALE" + i);
//                        toilet.showToilet();
                    }
                }catch (InterruptedException ex){

                }
            }
        });


        Thread t6 = new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    for(int i=1000;i<1050;i++){
                        System.out.println("Trying to enter toilet " + "FEMALE" + i);
                        toilet.enterFemale("FEMALE" + i);
//                        toilet.showToilet();
                    }
                }catch (InterruptedException ex){

                }
            }
        });

        t1.start();
        t2.start();
        t3.start();
        t4.start();
        t5.start();
        t6.start();


        t1.join();
        t2.join();
        t3.join();
        t4.join();
        t5.join();
        t6.join();

        System.out.print("Sunil Singh=====");
    }
}