diff --git a/interop/core/src/main/java/org/teavm/interop/DirectMalloc.java b/interop/core/src/main/java/org/teavm/interop/DirectMalloc.java
index f26ab0c49..b605abb92 100644
--- a/interop/core/src/main/java/org/teavm/interop/DirectMalloc.java
+++ b/interop/core/src/main/java/org/teavm/interop/DirectMalloc.java
@@ -26,7 +26,10 @@ package org.teavm.interop;
  * 
  * @author lax1dude
  */
-public class DirectMalloc {
+public final class DirectMalloc {
+
+    private DirectMalloc() {
+    }
 
     @UnsupportedOn({Platforms.JAVASCRIPT, Platforms.WEBASSEMBLY, Platforms.C})
     public static native Address malloc(int sizeBytes);
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmGCTask.java b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmGCTask.java
index 7e244fdf2..0ad674a00 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmGCTask.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmGCTask.java
@@ -36,6 +36,9 @@ public abstract class GenerateWasmGCTask extends TeaVMTask {
         getDebugInfoLocation().convention(WasmDebugInfoLocation.EXTERNAL);
         getSourceMap().convention(false);
         getSourceFilePolicy().convention(SourceFilePolicy.LINK_LOCAL_FILES);
+        getDirectMallocSupport().convention(false);
+        getMinHeapSize().convention(1);
+        getMaxHeapSize().convention(16);
     }
 
     @Input
@@ -98,7 +101,7 @@ public abstract class GenerateWasmGCTask extends TeaVMTask {
         TaskUtils.applySourceFiles(getSourceFiles(), builder);
         TaskUtils.applySourceFilePolicy(getSourceFilePolicy(), builder);
         builder.setDirectMallocSupport(getDirectMallocSupport().getOrElse(false));
-        builder.setMinHeapSize(getMinHeapSize().getOrElse(0) * MB);
-        builder.setMaxHeapSize(getMaxHeapSize().getOrElse(0) * MB);
+        builder.setMinHeapSize(getMinHeapSize().get() * MB);
+        builder.setMaxHeapSize(getMaxHeapSize().get() * MB);
     }
 }