Index: RunnableForThrougputComputation.java
===================================================================
--- RunnableForThrougputComputation.java	(revision 2296)
+++ RunnableForThrougputComputation.java	(working copy)
@@ -1,5 +1,7 @@
 package ch.qos.logback.core.issue;
 
+import java.util.concurrent.atomic.AtomicBoolean;
+
 /**
  * A runnable with 'done' and 'counter' fields.
  * 
@@ -8,7 +10,7 @@
  */
 abstract public class RunnableForThrougputComputation implements Runnable {
 
-  protected boolean done = false;
+  protected AtomicBoolean done = new AtomicBoolean();
   protected long counter = 0;
   
   public long getCounter() {
@@ -16,11 +18,11 @@
   }
 
   public void setDone(boolean done) {
-    this.done = done;
+    this.done.set(done);
   }
 
   public boolean isDone() {
-    return done;
+    return done.get();
   }
   
 }
Index: SelectiveLockRunnable.java
===================================================================
--- SelectiveLockRunnable.java	(revision 2296)
+++ SelectiveLockRunnable.java	(working copy)
@@ -47,7 +47,7 @@
       FAIR_LOCK.lock();
       counter++;
       FAIR_LOCK.unlock();
-      if (done) {
+      if (isDone()) {
         return;
       }
     }
@@ -58,7 +58,7 @@
       UNFAIR_LOCK.lock();
       counter++;
       UNFAIR_LOCK.unlock();
-      if (done) {
+      if (isDone()) {
         return;
       }
     }
@@ -67,7 +67,7 @@
   void nolockRun() {
     for (;;) {
       counter++;
-      if (done) {
+      if (isDone()) {
         return;
       }
     }
@@ -78,7 +78,7 @@
       synchronized (LOCK) {
         counter++;
       }
-      if (done) {
+      if (isDone()) {
         return;
       }
     }