VM stops if RuntimeException is not handled in a thread.

An error is thrown in context.js:
 TypeError: caller is undefined

tests/automation.js

@@ -41,7 +41,7 @@ casper.test.begin("unit tests", 5 + gfxTests.length, function(test) {
     .withFrame(0, function() {
         casper.waitForText("DONE", function() {
             var content = this.getPageContent();
-            if (content.contains("DONE: 70965 pass, 0 fail, 180 known fail, 0 unknown pass")) {
+            if (content.contains("DONE: 70966 pass, 0 fail, 180 known fail, 0 unknown pass")) {
               test.pass('main unit tests');
             } else {
               this.debugPage();

tests/java/lang/TestThread.java

@@ -0,0 +1,28 @@
+package java.lang;
+
+import gnu.testlet.Testlet;
+import gnu.testlet.TestHarness;
+
+public class TestThread implements Testlet {
+    private boolean result = false;
+
+    class RuntimeExceptionThread extends Thread {
+        public void run() {
+             throw new RuntimeException("runtime exception");
+        }
+    }
+
+    public void test(TestHarness th) {
+        try {
+            Thread t = new RuntimeExceptionThread();
+            t.start();
+            t.join();
+            result = true;
+        } catch (InterruptedException e) {
+            th.fail("unexpected InterruptedException");
+        }
+
+        th.check(result);
+    }
+}
+

vm.js

@@ -103,10 +103,26 @@ VM.execute = function(ctx) {
 
                 return;
             }
+
+            if (ctx.frames.length == 1) {
+                break;
+            }
+
             popFrame(0);
         } while (frame.methodInfo);
+
         ctx.kill();
-        throw new Error(buildExceptionLog(ex, stackTrace));
+
+        if (ctx.thread && ctx.thread.waiting && ctx.thread.waiting.length > 0) {
+            console.error(buildExceptionLog(ex, stackTrace));
+
+            ctx.thread.waiting.forEach(function(waitingCtx, n) {
+                ctx.thread.waiting[n] = null;
+                waitingCtx.wakeup(ctx.thread);
+            });
+        } else {
+          throw new Error(buildExceptionLog(ex, stackTrace));
+        }
     }
 
     function checkArrayAccess(refArray, idx) {