Instruction: Use java programming language. Make sure to put

comments at each line of our code. If the solution does not have any comments,

you will be deducted $25\%$ of your grade.

Question $1$:

Suppose we have a class:

public class Foo $\{$

public void first$()\{$ print$("$first$")$; $\}$

public void second$()\{$ print$("$second$")$; $\}$

public void third$()\{$ print$("$third$")$; $\}$

$\}$

The same instance of Foo will be passed to three different threads. Thread A will call first$(),$ thread B will

call second$(),$ and thread $C$ will call third$().$ Design a mechanism and modify the program to ensure that

second$()$ is executed after first$(),$ and third$()$ is executed after second$().$

Note:

We do not know how the threads will be scheduled in the operating system, even though the numbers

in the input seem to imply the ordering. The input format you see is mainly to ensure our tests'

comprehensiveness.

Example $1$:

Input: nums $=[1,2,3]$

Output: "firstsecondthird"

Explanation: There are three threads being fired asynchronously. The input $1,2,3$ means thread A calls

first$(),$ thread B calls second$(),$ and thread C calls third$().$ "firstsecondthird" is the correct output. Use the following starter code:

Java class Foo $\{$ public Foo$()\{\}$ public void first$($Runnable printFirst$)$ throws InterruptedException $\{//$ printFirst.run$()$ outputs "first". Do not change or remove this line. printFirst.run$()$; $\}$ public void second$($Runnable printSecond$)$ throws InterruptedException $\{//$ printSecond.run$()$ outputs "second". Do not change or remove this line. printSecond.run$()$; $\}$ public void third$($Runnable printThird$)$ throws InterruptedException $\{//$ printThird.run$()$ outputs "third". Do not change or remove this line. printThird.run$()$; $\}\}$