ADDITIONAL SYSTEM INFORMATION :
macOS Catalina
java version "1.8.0_212"
Java(TM) SE Runtime Environment (build 1.8.0_212-b10)
Java HotSpot(TM) 64-Bit Server VM (build 25.212-b10, mixed mode)

A DESCRIPTION OF THE PROBLEM :
PriorityQueue remove() method returns incorrect value when using lambda expression to specify the comparator. However, when using Comparator.comparingInt it returns correct value.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
//RUN THE CODE BELOW. THE SMALLER VALUE -2147483648 SHOULD BE RETURNED IN BOTH CASES, //HOWEVER, WHEN USING A LAMBDA EXPRESSION THE LARGER OF THE TWO VALUES IS RETURNED


package com.company.practice;

import java.util.Comparator;
import java.util.PriorityQueue;

public class PriQueue {

    public static void main(String[] args) {
        PriorityQueue heap1 = new PriorityQueue<Integer>((a1, a2) -> (a1-a2));
        heap1.add(2147483647);
        heap1.add(-2147483648);
        System.out.println("Result from heap1: " + heap1.remove());

        PriorityQueue heap2 = new PriorityQueue<Integer>(Comparator.comparingInt(a -> a));
        heap2.add(2147483647);
        heap2.add(-2147483648);
        System.out.println("Result from heap2: " + heap2.remove());

    }
}

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Result from heap1: -2147483648
Result from heap2: -2147483648
ACTUAL -
Result from heap1: 2147483647
Result from heap2: -2147483648

---------- BEGIN SOURCE ----------
package com.company.practice;

import java.util.Comparator;
import java.util.PriorityQueue;

public class PriQueue {

    public static void main(String[] args) {
        PriorityQueue heap1 = new PriorityQueue<Integer>((a1, a2) -> (a1-a2));
        heap1.add(2147483647);
        heap1.add(-2147483648);
        System.out.println("Result from heap1: " + heap1.remove());

        PriorityQueue heap2 = new PriorityQueue<Integer>(Comparator.comparingInt(a -> a));
        heap2.add(2147483647);
        heap2.add(-2147483648);
        System.out.println("Result from heap2: " + heap2.remove());

    }
}
---------- END SOURCE ----------