diff --git a/WHATSNEW b/WHATSNEW
index 99916f40f..1db16d667 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -317,6 +317,9 @@ Other changes:
 Fixed bugs:
 -----------
 
+* Killing a thread running <java fork="true"> (e.g. from an IDE) would
+  not stop the forked process. Bugzilla 31928.
+
 * Programs run with <java fork="true"> can now accept standard input
   from the Ant console.  (Programs run with <java fork="false"> could
   already do so.)  Bugzilla 24918.
diff --git a/src/main/org/apache/tools/ant/taskdefs/Execute.java b/src/main/org/apache/tools/ant/taskdefs/Execute.java
index e2da15bb3..09b762418 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Execute.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Execute.java
@@ -27,11 +27,8 @@ import java.io.PrintWriter;
 import java.io.StringReader;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
-import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
-import java.util.Map;
-import java.util.Set;
 import java.util.Vector;
 
 import org.apache.tools.ant.BuildException;
@@ -40,7 +37,6 @@ import org.apache.tools.ant.Task;
 import org.apache.tools.ant.taskdefs.condition.Os;
 import org.apache.tools.ant.types.Commandline;
 import org.apache.tools.ant.util.FileUtils;
-import org.apache.tools.ant.util.JavaEnvUtils;
 
 /**
  * Runs an external program.
@@ -485,6 +481,10 @@ public class Execute {
                 watchdog.checkException();
             }
             return getExitValue();
+        } catch (ThreadDeath t) {
+            // #31928: forcibly kill it before continuing.
+            process.destroy();
+            throw t;
         } finally {
             // remove the process to the list of those to destroy if
             // the VM exits