diff --git a/classlib/src/main/java/org/teavm/classlib/impl/JCLPlugin.java b/classlib/src/main/java/org/teavm/classlib/impl/JCLPlugin.java
index 4c9a283a2..e3af5aa47 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/JCLPlugin.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/JCLPlugin.java
@@ -29,6 +29,7 @@ import org.teavm.classlib.impl.currency.CurrencyHelper;
 import org.teavm.classlib.impl.lambda.LambdaMetafactorySubstitutor;
 import org.teavm.classlib.impl.tz.DateTimeZoneProvider;
 import org.teavm.classlib.impl.tz.DateTimeZoneProviderIntrinsic;
+import org.teavm.classlib.impl.tz.DateTimeZoneProviderPatch;
 import org.teavm.classlib.impl.tz.TimeZoneGenerator;
 import org.teavm.classlib.impl.unicode.AvailableLocalesMetadataGenerator;
 import org.teavm.classlib.impl.unicode.CLDRHelper;
@@ -147,6 +148,15 @@ public class JCLPlugin implements TeaVMPlugin {
 
         installMetadata(host.getService(MetadataRegistration.class));
         host.add(new DeclaringClassDependencyListener());
+        applyTimeZoneDetection(host);
+    }
+
+    private void applyTimeZoneDetection(TeaVMHost host) {
+        boolean autodetect = Boolean.parseBoolean(
+                host.getProperties().getProperty("java.util.TimeZone.autodetect", "false"));
+        if (!autodetect) {
+            host.add(new DateTimeZoneProviderPatch());
+        }
     }
 
     private void installMetadata(MetadataRegistration reg) {
diff --git a/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProvider.java b/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProvider.java
index cdc367da4..730402459 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProvider.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProvider.java
@@ -23,7 +23,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.PriorityQueue;
 import java.util.Set;
-import org.teavm.backend.javascript.spi.GeneratedBy;
 import org.teavm.classlib.impl.Base46;
 import org.teavm.classlib.impl.CharFlow;
 import org.teavm.interop.Import;
@@ -73,14 +72,7 @@ public final class DateTimeZoneProvider {
         return ids.toArray(new String[ids.size()]);
     }
 
-    @GeneratedBy(DateTimeZoneProviderGenerator.class)
-    private static native boolean timeZoneDetectionEnabled();
-
     public static DateTimeZone detectTimezone() {
-        if (!timeZoneDetectionEnabled()) {
-            return null;
-        }
-
         List<Score> zones = new ArrayList<>();
         long time = System.currentTimeMillis();
         int offset = -getNativeOffset(System.currentTimeMillis());
diff --git a/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProviderGenerator.java b/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProviderGenerator.java
deleted file mode 100644
index 1138dfd37..000000000
--- a/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProviderGenerator.java
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- *  Copyright 2017 Alexey Andreev.
- *
- *  Licensed under the Apache License, Version 2.0 (the "License");
- *  you may not use this file except in compliance with the License.
- *  You may obtain a copy of the License at
- *
- *       http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS,
- *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
- */
-package org.teavm.classlib.impl.tz;
-
-import java.io.IOException;
-import org.teavm.backend.javascript.codegen.SourceWriter;
-import org.teavm.backend.javascript.spi.Generator;
-import org.teavm.backend.javascript.spi.GeneratorContext;
-import org.teavm.model.MethodReference;
-
-public class DateTimeZoneProviderGenerator implements Generator {
-    @Override
-    public void generate(GeneratorContext context, SourceWriter writer, MethodReference methodRef) throws IOException {
-        boolean autodetect = Boolean.parseBoolean(
-                context.getProperties().getProperty("java.util.TimeZone.autodetect", "false"));
-        writer.append("return " + autodetect + ";");
-    }
-}
diff --git a/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProviderPatch.java b/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProviderPatch.java
new file mode 100644
index 000000000..03968a4a3
--- /dev/null
+++ b/classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProviderPatch.java
@@ -0,0 +1,45 @@
+/*
+ *  Copyright 2020 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.classlib.impl.tz;
+
+import java.util.TimeZone;
+import org.teavm.model.ClassHolder;
+import org.teavm.model.ClassHolderTransformer;
+import org.teavm.model.ClassHolderTransformerContext;
+import org.teavm.model.MethodDescriptor;
+import org.teavm.model.MethodHolder;
+import org.teavm.model.emit.ProgramEmitter;
+
+public class DateTimeZoneProviderPatch implements ClassHolderTransformer {
+    @Override
+    public void transformClass(ClassHolder cls, ClassHolderTransformerContext context) {
+        if (cls.getName().equals(DateTimeZoneProvider.class.getName())) {
+            MethodHolder method = cls.getMethod(new MethodDescriptor("detectTimezone", DateTimeZone.class));
+            if (method != null) {
+                method.setProgram(null);
+                ProgramEmitter pe = ProgramEmitter.create(method, context.getHierarchy());
+                pe.constantNull(DateTimeZone.class).returnValue();
+            }
+        } else if (cls.getName().equals(TimeZone.class.getName())) {
+            MethodHolder method = cls.getMethod(new MethodDescriptor("detectTimezone", TimeZone.class));
+            if (method != null) {
+                method.setProgram(null);
+                ProgramEmitter pe = ProgramEmitter.create(method, context.getHierarchy());
+                pe.constantNull(TimeZone.class).returnValue();
+            }
+        }
+    }
+}
diff --git a/classlib/src/main/java/org/teavm/classlib/impl/tz/TimeZoneGenerator.java b/classlib/src/main/java/org/teavm/classlib/impl/tz/TimeZoneGenerator.java
index 77c04ee80..4dca03ad1 100644
--- a/classlib/src/main/java/org/teavm/classlib/impl/tz/TimeZoneGenerator.java
+++ b/classlib/src/main/java/org/teavm/classlib/impl/tz/TimeZoneGenerator.java
@@ -71,13 +71,13 @@ public class TimeZoneGenerator implements MetadataGenerator {
     public ResourceMap<ResourceMap<TimeZoneResource>> generateMetadata(
             MetadataGeneratorContext context, MethodReference method) {
         ResourceMap<ResourceMap<TimeZoneResource>> result = context.createResourceMap();
-        ZoneInfoCompiler compiler = new ZoneInfoCompiler();
         Collection<StorableDateTimeZone> zones;
         try (InputStream input = context.getClassLoader().getResourceAsStream("org/teavm/classlib/impl/tz/cache")) {
             if (input != null) {
                 TimeZoneCache cache = new TimeZoneCache();
                 zones = cache.read(new BufferedInputStream(input)).values();
             } else {
+                ZoneInfoCompiler compiler = new ZoneInfoCompiler();
                 compile(compiler, context.getClassLoader());
                 zones = compiler.compile().values();
             }
diff --git a/classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java b/classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java
index 5647b4b10..285c18e0f 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/util/TTimeZone.java
@@ -152,16 +152,19 @@ public abstract class TTimeZone implements Serializable, Cloneable {
      */
     public static TTimeZone getDefault() {
         if (defaultTz == null) {
-            DateTimeZone innerTz = DateTimeZoneProvider.detectTimezone();
-            if (innerTz != null) {
-                defaultTz = new TIANATimeZone(innerTz);
-            } else {
-                defaultTz = TTimeZone.getTimeZone("UTC");
+            defaultTz = detectTimezone();
+            if (defaultTz == null) {
+                defaultTz = TTimeZone.GMT;
             }
         }
         return (TTimeZone) defaultTz.clone();
     }
 
+    private static TTimeZone detectTimezone() {
+        DateTimeZone innerTz = DateTimeZoneProvider.detectTimezone();
+        return innerTz != null ? new TIANATimeZone(innerTz) : null;
+    }
+
     /**
      * Gets the LONG name for this {@code TimeZone} for the default {@code Locale} in standard
      * time. If the name is not available, the result is in the format
diff --git a/tools/cli/pom.xml b/tools/cli/pom.xml
index 93a694ed3..10216b1d4 100644
--- a/tools/cli/pom.xml
+++ b/tools/cli/pom.xml
@@ -136,6 +136,7 @@
                   <exclude>junit:junit</exclude>
                   <exclude>com.fasterxml.jackson.core:jackson-annotations</exclude>
                   <exclude>org.mozilla:rhino</exclude>
+                  <exclude>joda-time:joda-time</exclude>
                 </excludes>
               </artifactSet>
               <transformers>
diff --git a/tools/idea/idea-artifacts/dep-pom.xml b/tools/idea/idea-artifacts/dep-pom.xml
index 4a6477e75..cf6327263 100644
--- a/tools/idea/idea-artifacts/dep-pom.xml
+++ b/tools/idea/idea-artifacts/dep-pom.xml
@@ -119,6 +119,7 @@
               <atrifactSet>
                 <excludes>
                   <exclude>com.jetbrains.intellij.idea:ideaIC:zip:*</exclude>
+                  <exclude>joda-time:joda-time</exclude>
                 </excludes>
               </atrifactSet>
               <createDependencyReducedPom>false</createDependencyReducedPom>