diff --git a/org.adempiere.base/src/org/compiere/model/MLocation.java b/org.adempiere.base/src/org/compiere/model/MLocation.java
index a03457b4c4..bce8c7112e 100644
--- a/org.adempiere.base/src/org/compiere/model/MLocation.java
+++ b/org.adempiere.base/src/org/compiere/model/MLocation.java
@@ -419,6 +419,12 @@ public class MLocation extends X_C_Location implements Comparator<Object>
 		return equals(cmp);
 	}	//	equals
 
+	public int hashCode()
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
+
 	/**
 	 * 	Print Address Reverse Order
 	 *	@return true if reverse depending on country
diff --git a/org.adempiere.base/src/org/compiere/model/MLookup.java b/org.adempiere.base/src/org/compiere/model/MLookup.java
index 020bd58603..8f84a1d4ca 100644
--- a/org.adempiere.base/src/org/compiere/model/MLookup.java
+++ b/org.adempiere.base/src/org/compiere/model/MLookup.java
@@ -276,6 +276,12 @@ public final class MLookup extends Lookup implements Serializable
 		}
 		return false;
 	}	//	equals
+	
+	public int hashCode()
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
 
 	/**
 	 *	Return Size
diff --git a/org.adempiere.base/src/org/compiere/model/MRfQResponseLineQty.java b/org.adempiere.base/src/org/compiere/model/MRfQResponseLineQty.java
index ba200cb4b7..28ea7556f4 100644
--- a/org.adempiere.base/src/org/compiere/model/MRfQResponseLineQty.java
+++ b/org.adempiere.base/src/org/compiere/model/MRfQResponseLineQty.java
@@ -231,6 +231,12 @@ public class MRfQResponseLineQty extends X_C_RfQResponseLineQty implements Compa
     	}
     	return false;
 	}	//	equals
+    
+    public int hashCode()
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
 
 	/**
 	 * 	Before Save
diff --git a/org.adempiere.base/src/org/compiere/model/MultiMap.java b/org.adempiere.base/src/org/compiere/model/MultiMap.java
index 4efe4e4a72..13eb594554 100644
--- a/org.adempiere.base/src/org/compiere/model/MultiMap.java
+++ b/org.adempiere.base/src/org/compiere/model/MultiMap.java
@@ -234,6 +234,12 @@ public final class MultiMap<K,V> implements Map<K,V>, Serializable
 	{
 		throw new java.lang.UnsupportedOperationException("Method equals() not implemented.");
 	}
+	
+	public int hashCode()
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
 
 	/**************************************************************************
 	 *  Returns class name and number of entries
diff --git a/org.adempiere.base/src/org/compiere/model/PO.java b/org.adempiere.base/src/org/compiere/model/PO.java
index 10f8dad895..d9c3038c66 100644
--- a/org.adempiere.base/src/org/compiere/model/PO.java
+++ b/org.adempiere.base/src/org/compiere/model/PO.java
@@ -313,6 +313,12 @@ public abstract class PO
 				return ((PO)cmp).get_ID() == get_ID();
 		return super.equals(cmp);
 	}	//	equals
+	
+	public int hashCode()
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
 
 	/**
 	 * 	Compare based on DocumentNo, Value, Name, Description
diff --git a/org.adempiere.base/src/org/compiere/print/CPaper.java b/org.adempiere.base/src/org/compiere/print/CPaper.java
index 1f91a54c43..ca70af8898 100644
--- a/org.adempiere.base/src/org/compiere/print/CPaper.java
+++ b/org.adempiere.base/src/org/compiere/print/CPaper.java
@@ -411,6 +411,12 @@ public class CPaper extends Paper
 		}
 		return false;
 	}	//	equals
+	
+	public int hashCode()
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
 
 	/*************************************************************************/
 
diff --git a/org.adempiere.base/src/org/compiere/util/MSort.java b/org.adempiere.base/src/org/compiere/util/MSort.java
index 37e50e067e..04d1492d0e 100644
--- a/org.adempiere.base/src/org/compiere/util/MSort.java
+++ b/org.adempiere.base/src/org/compiere/util/MSort.java
@@ -164,6 +164,12 @@ public final class MSort implements Comparator<Object>, Serializable
 		}
 		return false;
 	}	//	equals
+	
+	public int hashCode()
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
 
 	/**
 	 * 	String Representation
diff --git a/org.adempiere.install/src/org/compiere/install/util/ALayoutConstraint.java b/org.adempiere.install/src/org/compiere/install/util/ALayoutConstraint.java
index 34474d0634..5554860dcc 100644
--- a/org.adempiere.install/src/org/compiere/install/util/ALayoutConstraint.java
+++ b/org.adempiere.install/src/org/compiere/install/util/ALayoutConstraint.java
@@ -104,6 +104,12 @@ public class ALayoutConstraint implements Comparable<Object>
 		return false;
 	}   //  equal
 
+	public int hashCode() 
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
+	
 	/**
 	 *  To String
 	 *  @return info
diff --git a/org.adempiere.ui.swing/src/org/compiere/apps/ALayoutConstraint.java b/org.adempiere.ui.swing/src/org/compiere/apps/ALayoutConstraint.java
index d517b7e14b..718fce2006 100644
--- a/org.adempiere.ui.swing/src/org/compiere/apps/ALayoutConstraint.java
+++ b/org.adempiere.ui.swing/src/org/compiere/apps/ALayoutConstraint.java
@@ -103,6 +103,12 @@ public class ALayoutConstraint implements Comparable<Object>
 			return compareTo(o) == 0;
 		return false;
 	}   //  equal
+	
+	public int hashCode() 
+	{
+	  assert false : "hashCode not designed";
+	  return 42; // any arbitrary constant will do
+	}
 
 	/**
 	 *  To String