CODEWITHSUNDEEP
javagarbage-collectiong1gc
brainchrist
brainchrist

Reputation: 184

G1 garbage collection causing variable value to be reset?

If I run the following code with the -XX:+UseG1GC flag, every couple of runs the cellSize_m variable will get set to 0 inside the loop and I'll get the "Now it's broken" printouts. What am I missing here?

public class BugTest
{
  public static void main(String[] args)
  {
    fillArray(20);
  }

  public static void fillArray(double cellSize)
  {
    final double cellSize_m = cellSize;
    Integer[] hemispheres = new Integer[565504];

    for (int i = 0; i < 565504; i++)
    {
      hemispheres[i] = i;
      if (cellSize_m == 0)
      {
        System.out.println("Now it's broken. Iteration: " + i + " " + cellSize_m);
      }
    }
    System.out.println("Incrementing Cell Size " + (cellSize_m + 1));
  }
}

I'm on windows 7 using 64bit Java 8 build 144.

Upvotes: 3

Views: 160

Answers (2)

user7796409
user7796409

Reputation: 21

I have reported a similar bug JDK-8165766 last year, but it doesn't seem Oracle eager to fix this over optimization issue caused G1GC failed on floating point computation.

Upvotes: 1

brainchrist
brainchrist

Reputation: 184

It seems to be a jdk bug. JDK-8186112

Upvotes: 0

Related Questions