How to make sure that one syncronization block executes after the other - multithreading

Question

I have Counter class with 3 methods out of which 2 are synchronized, I want increment() to execute first and then the count(), so that count for each thread should always be 3000.
Instead of calling the count() from run() I can call it from within increment() is the only approach I can think of, Is there any other way to do So?
class Counter {
int count=0;
void print() {
System.out.println("Print called by: "+Thread.currentThread().getName());
}
synchronized void increment()
{
for(int i=1;i<=3000;i++)
count++;
}
synchronized void getCount() {
System.out.println(count);
count =0;
}
}
class MyThread1 extends Thread {
Counter c;
MyThread1(Counter c) {
this.c = c;
}
public void run() {
c.print();
c.increment();
c.getCount();
}
}
class MyThread2 extends Thread {
Counter c;
MyThread2(Counter c) {
this.c = c;
}
public void run() {
c.print();
c.increment();
c.getCount();
}
}
public class Demo {
public static void main(String args[]) {
Counter obj = new Counter();
MyThread1 t1 = new MyThread1(obj);
MyThread2 t2 = new MyThread2(obj);
t1.start();
t2.start();
}
}
Expected O/P in each case:
//The printing of "Print called by:" statement can be in any order as it's not synchronized but the count for each thread should always be 3000
Print called by: Thread-0
Print called by: Thread-1
3000
3000

Answer 1

Working example for my comment (You don't need MyThread1 and MyThread2):
public class Demo {
public static void main(String[] args) {
Counter obj = new Counter();
MyThread t1 = new MyThread(obj);
MyThread t2 = new MyThread(obj);
t1.start();
t2.start();
}
}
class Counter {
private final ThreadLocal<Integer> count = new ThreadLocal<Integer>() {
#Override
protected Integer initialValue() {
return 0;
}
};
void print() {
System.out.println("Print called by: " + Thread.currentThread().getName());
}
void increment() {
for (int i = 1; i <= 3000; i++)
count.set(count.get() + 1);
}
void getCount() {
System.out.println(count.get());
count.set(0);
}
}
class MyThread extends Thread {
Counter c;
MyThread(Counter c) {
this.c = c;
}
public void run() {
c.print();
c.increment();
c.getCount();
}
}

Answer 2

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class Demo {
public static void main(String args[]) {
Counter obj = new Counter();
MyThread t1 = new MyThread(obj);
MyThread t2 = new MyThread(obj);
t1.start();
t2.start();
}
}
class Counter {
Lock lock = new ReentrantLock();
int count = 0;
void print() {
System.out.println("Print called by: " + Thread.currentThread().getName());
}
void increment() {
lock.lock();
for (int i = 1; i <= 3000; i++)
count++;
}
void getCount() {
System.out.println(count);
count = 0;
lock.unlock();
}
}
class MyThread extends Thread {
Counter c;
MyThread(Counter c) {
this.c = c;
}
public void run() {
c.print();
c.increment();
c.getCount();
}
}

Answer 3

You can use synchronized to block a thread.
here the example:
public void run() {
synchronized (Thread.class) {
c.print();
c.increment();
c.getCount();
}
}
synchronized needs an object as param, please use same object for both class MyThread1 and MyThread2
read https://docs.oracle.com/javase/tutorial/essential/concurrency/locksync.html for more details.