diff --git a/src/main/org/apache/tools/ant/types/Resource.java b/src/main/org/apache/tools/ant/types/Resource.java
index b4f9964f6..4893fa44a 100644
--- a/src/main/org/apache/tools/ant/types/Resource.java
+++ b/src/main/org/apache/tools/ant/types/Resource.java
@@ -201,8 +201,9 @@ public class Resource implements Cloneable, Comparable {
         try {
             return super.clone();
         } catch (CloneNotSupportedException e) {
-            throw new Error("CloneNotSupportedException for a "
-                            + "Clonable Resource caught?");
+            throw new UnsupportedOperationException(
+                    "CloneNotSupportedException for a Resource caught. "+
+                    "Derived classes must support cloning.");
         }
     }
 
diff --git a/src/main/org/apache/tools/bzip2/CBZip2InputStream.java b/src/main/org/apache/tools/bzip2/CBZip2InputStream.java
index be62f15e1..e2502958d 100644
--- a/src/main/org/apache/tools/bzip2/CBZip2InputStream.java
+++ b/src/main/org/apache/tools/bzip2/CBZip2InputStream.java
@@ -190,10 +190,10 @@ public class CBZip2InputStream extends InputStream implements BZip2Constants {
             return -1;
 
         case START_BLOCK_STATE:
-            throw new Error();
+            throw new IllegalStateException();
 
         case RAND_PART_A_STATE:
-            throw new Error();
+            throw new IllegalStateException();
 
         case RAND_PART_B_STATE:
             setupRandPartB();
@@ -204,7 +204,7 @@ public class CBZip2InputStream extends InputStream implements BZip2Constants {
             break;
 
         case NO_RAND_PART_A_STATE:
-            throw new Error();
+            throw new IllegalStateException();
 
         case NO_RAND_PART_B_STATE:
             setupNoRandPartB();
@@ -215,7 +215,7 @@ public class CBZip2InputStream extends InputStream implements BZip2Constants {
             break;
 
         default:
-            throw new Error();
+            throw new IllegalStateException();
         }
 
         return retChar;