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8199435: Unsafe publication of java.util.Properties.map

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Reviewed-by: dholmes, psandoz, plevart, bchristi
This commit is contained in:
Claes Redestad 2018-06-20 17:06:24 +02:00
parent 561ec75b9b
commit edd5002b4e
1 changed files with 14 additions and 5 deletions
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19
src/java.base/share/classes/java/util/Properties.java
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@ -47,6 +47,7 @@ import java.util.function.BiFunction;
import java.util.function.Function;
import jdk.internal.misc.SharedSecrets;
import jdk.internal.misc.Unsafe;
import jdk.internal.util.xml.PropertiesDefaultHandler;
/**
@ -140,7 +141,9 @@ class Properties extends Hashtable<Object,Object> {
/**
* use serialVersionUID from JDK 1.1.X for interoperability
*/
private static final long serialVersionUID = 4112578634029874840L;
private static final long serialVersionUID = 4112578634029874840L;
private static final Unsafe UNSAFE = Unsafe.getUnsafe();
/**
* A property list that contains default values for any keys not
@ -148,7 +151,7 @@ class Properties extends Hashtable<Object,Object> {
*
* @serial
*/
protected Properties defaults;
protected volatile Properties defaults;
/**
* Properties does not store values in its inherited Hashtable, but instead
@ -156,7 +159,7 @@ class Properties extends Hashtable<Object,Object> {
* simple read operations. Writes and bulk operations remain synchronized,
* as in Hashtable.
*/
private transient ConcurrentHashMap<Object, Object> map;
private transient volatile ConcurrentHashMap<Object, Object> map;
/**
* Creates an empty property list with no default values.
@ -200,6 +203,9 @@ class Properties extends Hashtable<Object,Object> {
super((Void) null);
map = new ConcurrentHashMap<>(initialCapacity);
this.defaults = defaults;
// Ensure writes can't be reordered
UNSAFE.storeFence();
}
/**
@ -1097,7 +1103,8 @@ class Properties extends Hashtable<Object,Object> {
public String getProperty(String key) {
Object oval = map.get(key);
String sval = (oval instanceof String) ? (String)oval : null;
return ((sval == null) && (defaults != null)) ? defaults.getProperty(key) : sval;
Properties defaults;
return ((sval == null) && ((defaults = this.defaults) != null)) ? defaults.getProperty(key) : sval;
}
/**
@ -1483,6 +1490,7 @@ class Properties extends Hashtable<Object,Object> {
@Override
void writeHashtable(ObjectOutputStream s) throws IOException {
var map = this.map;
List<Object> entryStack = new ArrayList<>(map.size() * 2); // an estimate
for (Map.Entry<Object, Object> entry : map.entrySet()) {
@ -1537,7 +1545,7 @@ class Properties extends Hashtable<Object,Object> {
.checkArray(s, Map.Entry[].class, HashMap.tableSizeFor((int)(elements / 0.75)));
// create CHM of appropriate capacity
map = new ConcurrentHashMap<>(elements);
var map = new ConcurrentHashMap<>(elements);
// Read all the key/value objects
for (; elements > 0; elements--) {
@ -1545,5 +1553,6 @@ class Properties extends Hashtable<Object,Object> {
Object value = s.readObject();
map.put(key, value);
}
this.map = map;
}
}