[Ikvm-developers] memory leak on C# side when using JAVA transient static objects

[Boilay, V. <Vin...@sw...>]

Hello

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I found a leak in my C#  code using IKVM'ized version of the following
BasisPoint  java class.

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It leaks like hell when calling toString on the C# side of things.

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It keeps allocating memory in the text.FieldPosition due to call to
text.NumberFormat due to call to DecimalFormat.

It seems that the transient static is not converted properly to a static
variable in here but is rather allocated each time and never released
form the heap.

=3D>

            private transient static final NumberFormat PERCENT_FORMAT =
=3D
new DecimalFormat("#.0000");

            private transient static final NumberFormat BP_FORMAT =3D =
new
DecimalFormat("##.00");

<=3D

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Very easy to reproduce on c# side by doing :

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      for (long i =3D 0; i < 10000000; i++)

      {

        BasisPoint bp =3D BasisPoint.fromPercent(4);

        s =3D bp.toString();

        counter++;

        if (i%50=3D=3D0)

          Thread.Sleep(50)

      }

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And you'll see memory growing, growing and growing

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PS: I ran the same for() test on pure java side and it does not leak.

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import java.io.Serializable;

import java.text.DecimalFormat;

import java.text.NumberFormat;

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public final class BasisPoint implements Comparable, Serializable {

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            private final int value;

            private static final double SCALE =3D 100000.0;

            private static final double PERCENT =3D 100.0;

            private static final double PERCENT_SCALE =3D PERCENT * =
SCALE;

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            private transient static final NumberFormat PERCENT_FORMAT =
=3D
new DecimalFormat("#.0000");

            private transient static final NumberFormat BP_FORMAT =3D =
new
DecimalFormat("##.00");

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            public static final BasisPoint ZERO =3D new BasisPoint(0);

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            public static final BasisPoint NULL =3D new
BasisPoint(Integer.MIN_VALUE);

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            private BasisPoint(final int value) {

                        this.value =3D value;

            }

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            public String toString() {

                        if (isEmpty()) {

                                    return " - ";

                        }

                        if (isSubPercent()) {

                                    return displayInBasisPoint();

                        } else {

                                    return displayInPercent();

                        }

            }

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            public String displayInBasisPoint() {

                        return BP_FORMAT.format(basisPointValue()) +
"bp";

            }

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            public String displayInPercent() {

                        return PERCENT_FORMAT.format(percentValue()) +
"%";

            }

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            public static BasisPoint fromPercent(double percent) {

                        return fromBasisPoint(percent * PERCENT);

            }

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            public static BasisPoint fromBasisPoint(double basisPoint) {

                        int bp =3D (int) Math.round(basisPoint * SCALE);

                        return new BasisPoint(bp);

            }

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            public double basisPointValue() {

                        return (value =3D=3D 0) ? 0.0 : value / SCALE;

            }

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            public double percentValue() {

                        return (value =3D=3D 0) ? 0.0 : value /
PERCENT_SCALE;

            }

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            public BasisPoint round(double coeff) {

                        int bp =3D (int) (Math.round(value / SCALE /
coeff) * SCALE * coeff);

                        return bp =3D=3D value ? this : new =
BasisPoint(bp);

            }

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            public boolean isSubPercent() {

                        return (value > 0) ? value < PERCENT_SCALE :
-value < PERCENT_SCALE;

            }

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            public int compareTo(Object arg) {

                        if (!(arg instanceof BasisPoint)) {

                                    throw new
IllegalArgumentException("Can only compare BasisPoint with BasisPoint
instances");

                        }

                        BasisPoint other =3D (BasisPoint) arg;

                        if (value =3D=3D other.value) {

                                    return 0;

                        }

                        return (value > other.value) ? 1 : -1;

            }

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            public boolean equals(Object arg) {

                        if (this =3D=3D arg) {

                                    return true;

                        }

                        if (!(arg instanceof BasisPoint)) {

                                    return false;

                        }

                        BasisPoint other =3D (BasisPoint) arg;

                        return value =3D=3D other.value;

            }

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            public int hashCode() {

                        return value;

            }

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}