diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java
index 676a9edf0..f27377f16 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TClass.java
@@ -153,6 +153,7 @@ public class TClass<T> extends TObject implements TAnnotatedElement {
         return Address.ofObject(this).<RuntimeClass>toStructure().simpleName;
     }
 
+    @DelegateTo("setSimpleNameCacheLowLevel")
     private void setSimpleNameCache(String value) {
         simpleName = value;
     }
diff --git a/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java b/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java
index bcbf6c6a3..d2b3a697b 100644
--- a/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java
+++ b/core/src/main/java/org/teavm/backend/c/generate/ClassGenerator.java
@@ -248,9 +248,10 @@ public class ClassGenerator {
         FieldReference[] instanceFields = new FieldReference[cls.getFields().size()];
         int instanceIndex = 0;
         for (FieldHolder field : cls.getFields()) {
-            if (field.hasModifier(ElementModifier.STATIC)) {
+            if (field.hasModifier(ElementModifier.STATIC) || isMonitorField(field.getReference())) {
                 continue;
             }
+
             String fieldName = context.getNames().forMemberField(field.getReference());
             structWriter.printStrictType(field.getType()).print(" ").print(fieldName).println(";");
             if (isReferenceType(field.getType())) {
@@ -267,6 +268,10 @@ public class ClassGenerator {
         structWriter.outdent().print("} ").print(name).println(";");
     }
 
+    private boolean isMonitorField(FieldReference field) {
+        return field.getClassName().equals("java.lang.Object") && field.getFieldName().equals("monitor");
+    }
+
     private void generateClassStaticFields(ClassHolder cls) {
         CodeWriter fieldsWriter = structuresWriter.fragment();