diff --git a/xtandempipeline/debian/changelog b/xtandempipeline/debian/changelog
index aeef40e070efb9702efbbe4124703ff3ea2cbe39..81357770c8bf41d4b51140d97f548b476a6c8b71 100644
--- a/xtandempipeline/debian/changelog
+++ b/xtandempipeline/debian/changelog
@@ -3,6 +3,7 @@ xtandempipeline (3.1.2-1) natty; urgency=low
   * Work In Progress
   * ODS export
   * Didier Chevret has found a bug (fixed in this version) : error writing MS sample name in project file
+  * HashCode collision problem on huge data file fixed for HashPeptide
 
  --  Olivier Langella <Olivier.Langella@moulon.inra.fr>  Sun, 8 May 2011 9:18:51 +0200
 
diff --git a/xtandempipeline/src/fr/inra/pappso/xtandempipeline/grouping/HashPeptide.java b/xtandempipeline/src/fr/inra/pappso/xtandempipeline/grouping/HashPeptide.java
index c906f26d3f15afc73412c5543348432658e74e70..60dc0535cd651c1ff5e55ef8528c1797ac57196a 100644
--- a/xtandempipeline/src/fr/inra/pappso/xtandempipeline/grouping/HashPeptide.java
+++ b/xtandempipeline/src/fr/inra/pappso/xtandempipeline/grouping/HashPeptide.java
@@ -19,12 +19,25 @@ public class HashPeptide extends HashKey4Groups {
 				+ sequence).hashCode();
 	}
 
+	@Override
+	public boolean equals(Object toCompare) {
+		if (this.hashCode() == toCompare.hashCode()) {
+			//very good idea Benoit !
+			HashPeptide toComparePeptide = (HashPeptide) toCompare;
+			if ((this.hashSampleScan == toComparePeptide.hashSampleScan)
+					&& (this.sequence == toComparePeptide.sequence)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	@Override
 	public String toString() {
-		return hashSampleScan.toString()+" "+sequence;
-	
+		return hashSampleScan.toString() + " " + sequence;
+
 	}
-	
+
 	@Override
 	public int hashCode() {
 		return this.hascode;