diff --git a/src/fr/devinsy/strings/StringListInputStream.java b/src/fr/devinsy/strings/StringListInputStream.java
index 0d235a9..9b49a9b 100644
--- a/src/fr/devinsy/strings/StringListInputStream.java
+++ b/src/fr/devinsy/strings/StringListInputStream.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013-2015,2017-2018 Christian Pierre MOMON
+ * Copyright (C) 2013-2020 Christian Pierre MOMON
  * 
  * This file is part of Devinsy-strings.
  * 
@@ -57,7 +57,7 @@ public class StringListInputStream extends InputStream
 	{
 		if (source == null)
 		{
-			throw new NullPointerException("source is null.");
+			throw new IllegalArgumentException("source is null.");
 		}
 		else
 		{
diff --git a/src/fr/devinsy/strings/StringListWriter.java b/src/fr/devinsy/strings/StringListWriter.java
index 4f58113..25b02b4 100644
--- a/src/fr/devinsy/strings/StringListWriter.java
+++ b/src/fr/devinsy/strings/StringListWriter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013-2018 Christian Pierre MOMON
+ * Copyright (C) 2013-2020 Christian Pierre MOMON
  * 
  * This file is part of Devinsy-strings.
  * 
@@ -57,7 +57,7 @@ public class StringListWriter extends Writer
 	{
 		if (target == null)
 		{
-			throw new NullPointerException("target is null.");
+			throw new IllegalArgumentException("target is null.");
 		}
 		else
 		{