Missing serialversionUID

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/compress/trunk@1656358 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/commons/compress/PasswordRequiredException.java b/src/main/java/org/apache/commons/compress/PasswordRequiredException.java
index 6532a3a..2be6f22 100644
--- a/src/main/java/org/apache/commons/compress/PasswordRequiredException.java
+++ b/src/main/java/org/apache/commons/compress/PasswordRequiredException.java
@@ -26,6 +26,8 @@
  */
 public class PasswordRequiredException extends IOException {
 
+    private static final long serialVersionUID = 1391070005491684483L;
+
     /**
      * Create a new exception.
      *