Summary

An IllegalArgumentException may be thrown by ZipFile::getComment if there is a problem decoding the bytes representing the Zip file comment.

Problem

ZipFile::getComment may throw an IllegalArgumentException if an error occurs when decoding the bytes which represent the Zip file comment. Unfortunately the specification for ZipFile::getComment does not specify that this method may throw an Exception.

Solution

In the event of an exception when decoding the byte array that represents the Zip file comment, ZipFile::getComment will now return null instead of a spurious IllegalArgumentException.

Specification

The ZipFile::getComment specification will be updated to the following

   diff --git a/src/java.base/share/classes/java/util/zip/ZipFile.java b/src/java.base/share/classes/java/util/zip/ZipFile.java
index 7281db3297b..dd8e8126c76 100644
--- a/src/java.base/share/classes/java/util/zip/ZipFile.java
+++ b/src/java.base/share/classes/java/util/zip/ZipFile.java
@@ -305,7 +305,9 @@ public ZipFile(File file, Charset charset) throws IOException
     }

     /**
-     * Returns the zip file comment, or null if none.
+     * Returns the zip file comment. If a comment does not exist or an error is
+     * encountered decoding the comment using the charset specified
+     * when opening the Zip file, then {@code null} is returned.
      *
      * @return the comment string for the zip file, or null if none
      *
@@ -319,7 +321,13 @@ public String getComment() {
             if (res.zsrc.comment == null) {
                 return null;
             }
-            return res.zsrc.zc.toString(res.zsrc.comment);
+            // If there is a problem decoding the byte array which represents
+            // the Zip file comment, return null;
+            try {
+                return res.zsrc.zc.toString(res.zsrc.comment);
+            } catch(IllegalArgumentException iae) {
+                return null;
+            }
         }
     }