From 64216d3ea9ba04ee54a6a33f3074d59f55a6e0ef Mon Sep 17 00:00:00 2001
From: Reinier Zwitserloot $LOCK
instead.
If you want, you can create these locks yourself. The $lock
and $LOCK
fields will of course not be generated if you
- already created them yourself. You can also choose to lock on another field, by using specifying it as parameter to the @Synchronized
- annotation. In this usage variant, the fields will not be created automatically, and you must explicitly create them yourself.
+ already created them yourself. You can also choose to lock on another field, by specifying it as parameter to the @Synchronized
+ annotation. In this usage variant, the fields will not be created automatically, and you must explicitly create them yourself, or an error will be emitted.
Locking on this
or your own class object can have unfortunate side-effects, as other code not under your control can lock on these
objects as well, which can cause race conditions and other nasty threading-related bugs.
@@ -48,6 +48,9 @@
If $lock
and/or $LOCK
are auto-generated, the fields are initialized with an empty Object[]
array, and not
just a new Object()
as most snippets showing this pattern in action use. Lombok does this because a new object is NOT
serializable, but 0-size array is. Therefore, using @Synchronized
will not prevent your object from being serialized.
+
+ If you'd like to know why a field is not automatically generated when you choose your own name for the lock object: Because otherwise making a typo + in the field name will result in a very hard to find bug!
-- cgit