ADDITIONAL SYSTEM INFORMATION :
OS - Ubuntu 18.04.1 LTS
Tested with both java version - 1.8.0_121
and java version - 12.0.2

A DESCRIPTION OF THE PROBLEM :
If the while body has a small number of instructions, then it won't break the while loop if the boolean condition changed externally.

I found a similar issue - https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8179334
however even when the while body is not empty, this can be reproducible, 
I have checked the bytecodes in this scenario, it seems for me jump instructions are correctly generated, hence I thought maybe some issue with the hotspot VM


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Code I have pasted in the source code section wouldn't exit the while loop. 



EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
While loop should exit
ACTUAL -
While loop keeps on running

---------- BEGIN SOURCE ----------
public class Main {     
     
        public static boolean classLevelVar = true;    
        public static long fact;    
     
        public static void main(String[] args) {    
                breakWhileUsingClassVar();    
        }    
        public static int breakWhileUsingClassVar() {    
                (new Thread(() -> {    
                        try {    
                                Thread.sleep(2000);    
                        } catch (InterruptedException e) {    
                        }    
                        classLevelVar = false;       
     
                        System.out.println("After changing the class level variable - " + classLevelVar);    
                })).start();    
                System.out.println("Before starting the while loop - " + classLevelVar);    
                while (classLevelVar) {    
                        for (int i = 2; i <= 999999999; i++) {    
                                fact = fact * i;    
                        }    
                        for (int i = 2; i <= 999999999; i++) {    
                                fact = fact * i;    
                        }    
                        //for (int i = 2; i <= 999999999; i++) {    
                        //        fact = fact * i;    
                        //}    
                }    
                // Below statement doesn't get hit, making the class level variable volatile solves the issue.    
                return 8;    
        }    
} 
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
If you make the condition boolean "classLevelVar" volatile, then it works, 
and if you uncomment the last for loop, then it works, (Basically if the logic inside while body exceeds a certain threshold, this works properly)
and if you put a SOUT inside the while loop, again it works.

FREQUENCY : always