stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

7080700: numAppContexts is accessed in non-threadsafe way in sun.awt.AppContext

Browse Source 
Replace a volatile integer with an AtomicInteger for numAppContexts

Reviewed-by: anthony, art, dholmes
This commit is contained in:
Anthony Petrov 2012-04-16 18:36:58 +04:00
parent afa494b2a5
commit 975313d5cc
1 changed files with 14 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
jdk/src/share/classes/sun/awt/AppContext.java
View File

@ -46,6 +46,7 @@ import sun.util.logging.PlatformLogger;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.atomic.AtomicInteger;
/**
* The AppContext is a table referenced by ThreadGroup which stores
@ -194,6 +195,15 @@ public final class AppContext {
return isDisposed;
}
/*
* The total number of AppContexts, system-wide. This number is
* incremented at the beginning of the constructor, and decremented
* at the end of dispose(). getAppContext() checks to see if this
* number is 1. If so, it returns the sole AppContext without
* checking Thread.currentThread().
*/
private static final AtomicInteger numAppContexts = new AtomicInteger(0);
static {
// On the main Thread, we get the ThreadGroup, make a corresponding
// AppContext, and instantiate the Java EventQueue. This way, legacy
@ -209,21 +219,11 @@ public final class AppContext {
parentThreadGroup = currentThreadGroup.getParent();
}
mainAppContext = new AppContext(currentThreadGroup);
numAppContexts = 1;
return null;
}
});
}
/*
* The total number of AppContexts, system-wide. This number is
* incremented at the beginning of the constructor, and decremented
* at the end of dispose(). getAppContext() checks to see if this
* number is 1. If so, it returns the sole AppContext without
* checking Thread.currentThread().
*/
private static volatile int numAppContexts;
/*
* The context ClassLoader that was used to create this AppContext.
*/
@ -243,7 +243,7 @@ public final class AppContext {
* @since 1.2
*/
AppContext(ThreadGroup threadGroup) {
numAppContexts++;
numAppContexts.incrementAndGet();
this.threadGroup = threadGroup;
threadGroup2appContext.put(threadGroup, this);
@ -278,7 +278,7 @@ public final class AppContext {
* @since 1.2
*/
public final static AppContext getAppContext() {
if (numAppContexts == 1) // If there's only one system-wide,
if (numAppContexts.get() == 1) // If there's only one system-wide,
return mainAppContext; // return the main system AppContext.
AppContext appContext = threadAppContext.get();
@ -513,7 +513,7 @@ public final class AppContext {
this.table.clear(); // Clear out the Hashtable to ease garbage collection
}
numAppContexts--;
numAppContexts.decrementAndGet();
mostRecentKeyValue = null;
}
@ -804,7 +804,7 @@ public final class AppContext {
return getAppContext().isDisposed();
}
public boolean isMainAppContext() {
return (numAppContexts == 1);
return (numAppContexts.get() == 1);
}
});
}