diff --git a/projects/Math/61/org/apache/commons/math/distribution/PoissonDistributionImpl.java b/projects/Math/61/org/apache/commons/math/distribution/PoissonDistributionImpl.java
index 148daad..0a81233 100644
--- a/projects/Math/61/org/apache/commons/math/distribution/PoissonDistributionImpl.java
+++ b/projects/Math/61/org/apache/commons/math/distribution/PoissonDistributionImpl.java
@@ -19,7 +19,7 @@
 import java.io.Serializable;
 
 import org.apache.commons.math.MathException;
-import org.apache.commons.math.MathRuntimeException;
+import org.apache.commons.math.exception.NotStrictlyPositiveException;
 import org.apache.commons.math.exception.util.LocalizedFormats;
 import org.apache.commons.math.special.Gamma;
 import org.apache.commons.math.util.MathUtils;
@@ -91,7 +91,7 @@ public PoissonDistributionImpl(double p) {
      */
     public PoissonDistributionImpl(double p, double epsilon, int maxIterations) {
         if (p <= 0) {
-            throw MathRuntimeException.createIllegalArgumentException(LocalizedFormats.NOT_POSITIVE_POISSON_MEAN, p);
+            throw new NotStrictlyPositiveException(LocalizedFormats.MEAN, p);
         }
         mean = p;
         normal = new NormalDistributionImpl(p, FastMath.sqrt(p));