diff --git a/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java b/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java
index 06939910d..037415775 100644
--- a/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java
+++ b/core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java
@@ -427,10 +427,12 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
 
             for (Map.Entry<? extends String, ? extends TeaVMEntryPoint> entry
                     : controller.getEntryPoints().entrySet()) {
-                sourceWriter.append("").append(entry.getKey()).ws().append("=").ws();
+                sourceWriter.append(entry.getKey()).ws().append("=").ws();
                 MethodReference ref = entry.getValue().getMethod();
                 sourceWriter.append("$rt_mainStarter(").appendMethodBody(ref);
                 sourceWriter.append(");").newLine();
+                sourceWriter.append(entry.getKey()).append(".").append("javaException").ws().append("=").ws()
+                        .append("$rt_javaException;").newLine();
             }
 
             for (RendererListener listener : rendererListeners) {
diff --git a/core/src/main/resources/org/teavm/backend/javascript/runtime.js b/core/src/main/resources/org/teavm/backend/javascript/runtime.js
index c925e1d15..aa5514158 100644
--- a/core/src/main/resources/org/teavm/backend/javascript/runtime.js
+++ b/core/src/main/resources/org/teavm/backend/javascript/runtime.js
@@ -255,7 +255,7 @@ function $rt_voidcls() {
 function $rt_throw(ex) {
     throw $rt_exception(ex);
 }
-var $rt_exceptionTag = Symbol("teavmException")
+var $rt_javaExceptionProp = Symbol("javaException")
 function $rt_exception(ex) {
     var err = ex.$jsException;
     if (!err) {
@@ -263,8 +263,7 @@ function $rt_exception(ex) {
         if (typeof Error.captureStackTrace === "function") {
             Error.captureStackTrace(err);
         }
-        err.$javaException = ex;
-        err[$rt_exceptionTag] = true;
+        err[$rt_javaExceptionProp] = ex;
         ex.$jsException = err;
         $rt_fillStack(err, ex);
     }
@@ -650,18 +649,16 @@ function $rt_intBitsToFloat(n) {
 }
 
 function $rt_javaException(e) {
-    return e instanceof Error && $rt_exceptionTag in e
-            && typeof e.$javaException === 'object' ? e.$javaException : null;
+    return e instanceof Error && typeof e[$rt_javaExceptionProp] === 'object' ? e[$rt_javaExceptionProp] : null;
 }
 function $rt_jsException(e) {
     return typeof e.$jsException === 'object' ? e.$jsException : null;
 }
 function $rt_wrapException(err) {
-    var ex = err.$javaException;
-    if (!ex || !($rt_exceptionTag in err)) {
+    var ex = err[$rt_javaExceptionProp];
+    if (!ex) {
         ex = $rt_createException($rt_str("(JavaScript) " + err.toString()));
-        err.$javaException = ex;
-        err[$rt_exceptionTag] = true;
+        err[$rt_javaExceptionProp] = ex;
         ex.$jsException = err;
         $rt_fillStack(err, ex);
     }
diff --git a/tests/src/test/js/frame.js b/tests/src/test/js/frame.js
index 5ce2fa112..524398d32 100644
--- a/tests/src/test/js/frame.js
+++ b/tests/src/test/js/frame.js
@@ -73,9 +73,10 @@ function launchTest(argument, callback) {
 
     function buildErrorMessage(e) {
         let stack = "";
-        if (e.$javaException && e.$javaException.constructor.$meta) {
-            stack = e.$javaException.constructor.$meta.name + ": ";
-            stack += e.$javaException.getMessage();
+        var je = main.javaException(e);
+        if (je && je.constructor.$meta) {
+            stack = je.constructor.$meta.name + ": ";
+            stack += je.getMessage();
             stack += "\n";
         }
         stack += e.stack;
diff --git a/tests/src/test/js/src/run-tests.js b/tests/src/test/js/src/run-tests.js
index e9a793c4b..db75e7d43 100644
--- a/tests/src/test/js/src/run-tests.js
+++ b/tests/src/test/js/src/run-tests.js
@@ -273,9 +273,10 @@ function runTeaVM() {
 
         function makeErrorMessage(message, e) {
             message.status = "failed";
-            if (e.$javaException) {
-                message.className = e.$javaException.constructor.name;
-                message.message = e.$javaException.getMessage();
+            var je = main.javaException(e);
+            if (je) {
+                message.className = je.constructor.name;
+                message.message = je.getMessage();
             } else {
                 message.className = Object.getPrototypeOf(e).name;
                 message.message = e.message;
diff --git a/tools/junit/src/main/resources/teavm-htmlunit-adapter.js b/tools/junit/src/main/resources/teavm-htmlunit-adapter.js
index 665a29526..61bc3d7a2 100644
--- a/tools/junit/src/main/resources/teavm-htmlunit-adapter.js
+++ b/tools/junit/src/main/resources/teavm-htmlunit-adapter.js
@@ -14,9 +14,10 @@ function runMain(argument, stackDecoder, callback) {
 
     function makeErrorMessage(message, e) {
         message.status = "exception";
-        if (e.$javaException) {
-            message.className = e.$javaException.constructor.name;
-            message.message = e.$javaException.getMessage();
+        var je = main.javaException(e);
+        if (je) {
+            message.className = je.constructor.name;
+            message.message = je.getMessage();
         } else {
             message.className = Object.getPrototypeOf(e).name;
             message.message = e.message;
diff --git a/tools/junit/src/main/resources/teavm-run-test.html b/tools/junit/src/main/resources/teavm-run-test.html
index 3033a70a5..401a69867 100644
--- a/tools/junit/src/main/resources/teavm-run-test.html
+++ b/tools/junit/src/main/resources/teavm-run-test.html
@@ -14,9 +14,10 @@
 
     function buildErrorMessage(e) {
         var stack = "";
-        if (e.$javaException && e.$javaException.constructor.$meta) {
-            stack = e.$javaException.constructor.$meta.name + ": ";
-            stack += e.$javaException.getMessage() || "";
+        var je = main.javaException(e);
+        if (je && je.constructor.$meta) {
+            stack = je.constructor.$meta.name + ": ";
+            stack += je.getMessage() || "";
             stack += "\n";
         }
         stack += e.stack;