diff --git a/lib/xdrgen/generators/java.rb b/lib/xdrgen/generators/java.rb
index 0c8f1cc44..40ecd0cec 100644
--- a/lib/xdrgen/generators/java.rb
+++ b/lib/xdrgen/generators/java.rb
@@ -218,7 +218,7 @@ def render_enum(enum, out)
         end
         out.puts <<-EOS.strip_heredoc
             default:
-              throw new RuntimeException("Unknown enum value: " + value);
+              throw new IllegalArgumentException("Unknown enum value: " + value);
           }
         }
 
diff --git a/lib/xdrgen/generators/java/XdrString.erb b/lib/xdrgen/generators/java/XdrString.erb
index 588220225..cceb6d475 100644
--- a/lib/xdrgen/generators/java/XdrString.erb
+++ b/lib/xdrgen/generators/java/XdrString.erb
@@ -29,7 +29,7 @@ public class XdrString implements XdrElement {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/block_comments.x/AccountFlags.java b/spec/output/generator_spec_java/block_comments.x/AccountFlags.java
index 8f861de28..aab0ec7bf 100644
--- a/spec/output/generator_spec_java/block_comments.x/AccountFlags.java
+++ b/spec/output/generator_spec_java/block_comments.x/AccountFlags.java
@@ -36,7 +36,7 @@ public static AccountFlags decode(XdrDataInputStream stream) throws IOException
     switch (value) {
       case 1: return AUTH_REQUIRED_FLAG;
       default:
-        throw new RuntimeException("Unknown enum value: " + value);
+        throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
 
diff --git a/spec/output/generator_spec_java/block_comments.x/XdrString.java b/spec/output/generator_spec_java/block_comments.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/block_comments.x/XdrString.java
+++ b/spec/output/generator_spec_java/block_comments.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/const.x/XdrString.java b/spec/output/generator_spec_java/const.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/const.x/XdrString.java
+++ b/spec/output/generator_spec_java/const.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/enum.x/Color.java b/spec/output/generator_spec_java/enum.x/Color.java
index 5cf79765a..55a7f5587 100644
--- a/spec/output/generator_spec_java/enum.x/Color.java
+++ b/spec/output/generator_spec_java/enum.x/Color.java
@@ -41,7 +41,7 @@ public static Color decode(XdrDataInputStream stream) throws IOException {
       case 1: return GREEN;
       case 2: return BLUE;
       default:
-        throw new RuntimeException("Unknown enum value: " + value);
+        throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
 
diff --git a/spec/output/generator_spec_java/enum.x/Color2.java b/spec/output/generator_spec_java/enum.x/Color2.java
index 49040b085..57053ce2f 100644
--- a/spec/output/generator_spec_java/enum.x/Color2.java
+++ b/spec/output/generator_spec_java/enum.x/Color2.java
@@ -41,7 +41,7 @@ public static Color2 decode(XdrDataInputStream stream) throws IOException {
       case 1: return GREEN2;
       case 2: return BLUE2;
       default:
-        throw new RuntimeException("Unknown enum value: " + value);
+        throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
 
diff --git a/spec/output/generator_spec_java/enum.x/MessageType.java b/spec/output/generator_spec_java/enum.x/MessageType.java
index c79e5e6df..1ea906d4b 100644
--- a/spec/output/generator_spec_java/enum.x/MessageType.java
+++ b/spec/output/generator_spec_java/enum.x/MessageType.java
@@ -81,7 +81,7 @@ public static MessageType decode(XdrDataInputStream stream) throws IOException {
       case 12: return FBA_QUORUMSET;
       case 13: return FBA_MESSAGE;
       default:
-        throw new RuntimeException("Unknown enum value: " + value);
+        throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
 
diff --git a/spec/output/generator_spec_java/enum.x/XdrString.java b/spec/output/generator_spec_java/enum.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/enum.x/XdrString.java
+++ b/spec/output/generator_spec_java/enum.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/nesting.x/UnionKey.java b/spec/output/generator_spec_java/nesting.x/UnionKey.java
index e1ce172b1..80278b683 100644
--- a/spec/output/generator_spec_java/nesting.x/UnionKey.java
+++ b/spec/output/generator_spec_java/nesting.x/UnionKey.java
@@ -41,7 +41,7 @@ public static UnionKey decode(XdrDataInputStream stream) throws IOException {
       case 2: return TWO;
       case 3: return OFFER;
       default:
-        throw new RuntimeException("Unknown enum value: " + value);
+        throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
 
diff --git a/spec/output/generator_spec_java/nesting.x/XdrString.java b/spec/output/generator_spec_java/nesting.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/nesting.x/XdrString.java
+++ b/spec/output/generator_spec_java/nesting.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/optional.x/XdrString.java b/spec/output/generator_spec_java/optional.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/optional.x/XdrString.java
+++ b/spec/output/generator_spec_java/optional.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/struct.x/XdrString.java b/spec/output/generator_spec_java/struct.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/struct.x/XdrString.java
+++ b/spec/output/generator_spec_java/struct.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/test.x/Color.java b/spec/output/generator_spec_java/test.x/Color.java
index 7670bcc14..2199ca352 100644
--- a/spec/output/generator_spec_java/test.x/Color.java
+++ b/spec/output/generator_spec_java/test.x/Color.java
@@ -41,7 +41,7 @@ public static Color decode(XdrDataInputStream stream) throws IOException {
       case 5: return BLUE;
       case 6: return GREEN;
       default:
-        throw new RuntimeException("Unknown enum value: " + value);
+        throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
 
diff --git a/spec/output/generator_spec_java/test.x/Nester.java b/spec/output/generator_spec_java/test.x/Nester.java
index 353bbe7ea..bc8bcce59 100644
--- a/spec/output/generator_spec_java/test.x/Nester.java
+++ b/spec/output/generator_spec_java/test.x/Nester.java
@@ -98,7 +98,7 @@ public static NestedEnum decode(XdrDataInputStream stream) throws IOException {
         case 0: return BLAH_1;
         case 1: return BLAH_2;
         default:
-          throw new RuntimeException("Unknown enum value: " + value);
+          throw new IllegalArgumentException("Unknown enum value: " + value);
       }
     }
 
diff --git a/spec/output/generator_spec_java/test.x/XdrString.java b/spec/output/generator_spec_java/test.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/test.x/XdrString.java
+++ b/spec/output/generator_spec_java/test.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);
diff --git a/spec/output/generator_spec_java/union.x/UnionKey.java b/spec/output/generator_spec_java/union.x/UnionKey.java
index 8e9a8658f..504e811cc 100644
--- a/spec/output/generator_spec_java/union.x/UnionKey.java
+++ b/spec/output/generator_spec_java/union.x/UnionKey.java
@@ -38,7 +38,7 @@ public static UnionKey decode(XdrDataInputStream stream) throws IOException {
       case 0: return ERROR;
       case 1: return MULTI;
       default:
-        throw new RuntimeException("Unknown enum value: " + value);
+        throw new IllegalArgumentException("Unknown enum value: " + value);
     }
   }
 
diff --git a/spec/output/generator_spec_java/union.x/XdrString.java b/spec/output/generator_spec_java/union.x/XdrString.java
index ea0967625..a51eead77 100644
--- a/spec/output/generator_spec_java/union.x/XdrString.java
+++ b/spec/output/generator_spec_java/union.x/XdrString.java
@@ -29,7 +29,7 @@ public void encode(XdrDataOutputStream stream) throws IOException {
   public static XdrString decode(XdrDataInputStream stream, int maxSize) throws IOException {
     int size = stream.readInt();
     if (size > maxSize) {
-      throw new InvalidClassException("String length " + size + " exceeds max size " + maxSize);
+      throw new IllegalArgumentException("String length " + size + " exceeds max size " + maxSize);
     }
     byte[] bytes = new byte[size];
     stream.read(bytes);