On 1/22/16 7:44 AM, Claes Redestad wrote:
It would seem the assessment that serialVersionUID is not needed when
using the serial proxy pattern might be misguided (or is this a bug in
ObjectInputStream)?
It is debate-able whether this is a test bug or not. But I think
we should not change the serialVersionUID for this class, whether
truly Serializable or not. Even though in practice it is not all
that useful.
Can you please revert the serialization parts of the change, and
rerun the test? To see if still passes or fails.
I backed out the serial version UID change and reran the test, same thing.
I dug deeper, as this is a bit vexxing...
While a static field does not in and of itself cause the generated UID to
change,
the private ZERO_LENGTH_ENUM_ARRAY is being accessed from SerializationProxy
class, thus javac generates a package-private synthetic method (access$000)
which
will be accounted for when generating serialVersionUID. That's unfortunate.
I ran a few experiments to confirm this:
- Adding a package-private static method to EnumSet makes the test fail
- Adding any static field and the test keep passing
So it seems our options here are limited.
I think this is a bug in the test (BogusEnumSet.java).
EnumSet, a class in the runtime, should never appear in a serialized stream,
thus it shouldn't have to declare a serialVersionUID in order to remain
compatible with anything.
The test deliberately attempts to create a serialized stream that should never
occur in actual use, so the test should be responsible for constructing that
stream properly. Unfortunately, the test doesn't actually construct that stream;
instead it's a bunch of hex constants.
It's tedious but not difficult to patch the constants with the modified value.
I've appended a patch below that does this, along with removing EnumSet's
serialVersionUID and restoring the @SuppressWarnings.
I can post a webrev if this doesn't come through properly.
s'marks
diff -r c421a3928efc -r 6de800698cf7
src/java.base/share/classes/java/util/EnumMap.java
--- a/src/java.base/share/classes/java/util/EnumMap.java Mon Jan 11 10:13:29
2016 -0800
+++ b/src/java.base/share/classes/java/util/EnumMap.java Fri Jan 22 10:42:24
2016 -0800
@@ -25,7 +25,6 @@
package java.util;
-import java.util.Map.Entry;
import jdk.internal.misc.SharedSecrets;
/**
@@ -125,8 +124,6 @@
return (V)(value == NULL ? null : value);
}
- private static final Enum<?>[] ZERO_LENGTH_ENUM_ARRAY = new Enum<?>[0];
-
/**
* Creates an empty enum map with the specified key type.
*
diff -r c421a3928efc -r 6de800698cf7
src/java.base/share/classes/java/util/EnumSet.java
--- a/src/java.base/share/classes/java/util/EnumSet.java Mon Jan 11 10:13:29
2016 -0800
+++ b/src/java.base/share/classes/java/util/EnumSet.java Fri Jan 22 10:42:24
2016 -0800
@@ -92,8 +92,6 @@
*/
final Enum<?>[] universe;
- private static Enum<?>[] ZERO_LENGTH_ENUM_ARRAY = new Enum<?>[0];
-
EnumSet(Class<E>elementType, Enum<?>[] universe) {
this.elementType = elementType;
this.universe = universe;
@@ -421,6 +419,9 @@
private static class SerializationProxy <E extends Enum<E>>
implements java.io.Serializable
{
+
+ private static final Enum<?>[] ZERO_LENGTH_ENUM_ARRAY = new Enum<?>[0];
+
/**
* The element type of this enum set.
*
diff -r c421a3928efc -r 6de800698cf7 test/java/util/EnumMap/EnumMapBash.java
--- a/test/java/util/EnumMap/EnumMapBash.java Mon Jan 11 10:13:29 2016 -0800
+++ b/test/java/util/EnumMap/EnumMapBash.java Fri Jan 22 10:42:24 2016 -0800
@@ -48,8 +48,6 @@
bash(Silly500.class);
}
- private static Enum[] ZERO_LENGTH_ENUM_ARRAY = new Enum[0];
-
static <T extends Enum<T>> void bash(Class<T> enumClass) {
Enum[] universe = enumClass.getEnumConstants();
diff -r c421a3928efc -r 6de800698cf7 test/java/util/EnumSet/BogusEnumSet.java
--- a/test/java/util/EnumSet/BogusEnumSet.java Mon Jan 11 10:13:29 2016 -0800
+++ b/test/java/util/EnumSet/BogusEnumSet.java Fri Jan 22 10:42:24 2016 -0800
@@ -32,6 +32,11 @@
public class BogusEnumSet {
public static void main(String[] args) throws Throwable {
+ // This test depends on the current serialVersionUID of EnumSet,
+ // which may change if the EnumSet class is modified.
+ // The current value is 4168005130090799668L = 0x39D7BA9531116234L
+ // If the value changes, it will have to be patched into the
+ // serialized byte stream below at the location noted.
byte[] serializedForm = {
(byte)0xac, (byte)0xed, 0x0, 0x5, 0x73, 0x72, 0x0, 0x18,
0x6a, 0x61, 0x76, 0x61, 0x2e, 0x75, 0x74, 0x69,
@@ -40,9 +45,10 @@
0x7e, (byte)0xb0, (byte)0xd0, 0x7e, 0x2, 0x0, 0x1, 0x4a, 0x0, 0x8,
0x65, 0x6c, 0x65, 0x6d, 0x65, 0x6e, 0x74, 0x73, 0x78, 0x72, 0x0,
0x11, 0x6a, 0x61, 0x76, 0x61, 0x2e, 0x75, 0x74, 0x69,
- 0x6c, 0x2e, 0x45, 0x6e, 0x75, 0x6d, 0x53, 0x65, 0x74, 0xe,
- 0x3, 0x21, 0x6a, (byte)0xcd, (byte)0x8c, 0x29, (byte)0xdd, 0x2,
- 0x0, 0x2, 0x4c, 0x0, 0xb, 0x65, 0x6c, 0x65, 0x6d, 0x65, 0x6e, 0x74,
+ 0x6c, 0x2e, 0x45, 0x6e, 0x75, 0x6d, 0x53, 0x65, 0x74,
+ // EnumSet's serialVersionUID is the following eight bytes
(big-endian)
+ 0x39, (byte)0xd7, (byte)0xba, (byte)0x95, 0x31, 0x11, 0x62, 0x34,
+ 0x2, 0x0, 0x2, 0x4c, 0x0, 0xb, 0x65, 0x6c, 0x65, 0x6d, 0x65, 0x6e,
0x74,
0x54, 0x79, 0x70, 0x65, 0x74, 0x0, 0x11, 0x4c, 0x6a, 0x61, 0x76,
0x61, 0x2f, 0x6c, 0x61, 0x6e, 0x67, 0x2f, 0x43, 0x6c, 0x61, 0x73,
0x73, 0x3b, 0x5b, 0x0, 0x8, 0x75, 0x6e, 0x69, 0x76, 0x65, 0x72,
