diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/GlobalSettings.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/GlobalSettings.java
index 12e9052c79f..6780ac695bd 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/GlobalSettings.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/GlobalSettings.java
@@ -38,12 +38,13 @@ public class GlobalSettings {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(GlobalSettings.class);
 
-    private static ThreadLocal<Properties> properties = new InheritableThreadLocal<Properties>() {
+    private static ThreadLocal<Properties> properties = new InheritableThreadLocal<>() {
         @Override
         protected Properties initialValue() {
             // avoid using System.getProperties().clone() which is broken in Gradle - see https://github.com/gradle/gradle/issues/17344
             Properties copy = new Properties();
-            copy.putAll(System.getProperties());
+            System.getProperties()
+                .forEach((k,v) -> copy.put(String.valueOf(k), String.valueOf(v)));
             return copy;
         }
     };
@@ -69,8 +70,10 @@ public class GlobalSettings {
     }
 
     public static void log() {
-        StringWriter stringWriter = new StringWriter();
-        properties.get().list(new PrintWriter(stringWriter));
-        LOGGER.debug("GlobalSettings: {}", stringWriter);
+        if(LOGGER.isDebugEnabled()) {
+            StringWriter stringWriter = new StringWriter();
+            properties.get().list(new PrintWriter(stringWriter));
+            LOGGER.debug("GlobalSettings: {}", stringWriter);
+        }
     }
 }
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/config/GlobalSettingsTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/config/GlobalSettingsTest.java
new file mode 100644
index 00000000000..fadea5ff40f
--- /dev/null
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/config/GlobalSettingsTest.java
@@ -0,0 +1,36 @@
+package org.openapitools.codegen.config;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import java.util.Properties;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatNoException;
+import org.slf4j.LoggerFactory;
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.Test;
+
+/**
+ * Test class for {@link GlobalSettings}
+ * @author Edoardo Patti
+ */
+public class GlobalSettingsTest {
+
+  private static final Object OBJECT = new Object();
+
+  @BeforeClass
+  public void setUp() {
+    ((Logger) LoggerFactory.getLogger(GlobalSettings.class)).setLevel(Level.DEBUG);
+    Properties props = new Properties(2);
+    props.put("test1", OBJECT);
+    props.put(OBJECT, "test2");
+    System.getProperties().putAll(props);
+  }
+
+  @Test
+  public void testNonStringSystemProperties() {
+    assertThat(GlobalSettings.getProperty(OBJECT.toString())).isNotNull();
+    assertThat(GlobalSettings.getProperty("test1")).isNotNull();
+    assertThatNoException().isThrownBy(GlobalSettings::log);
+  }
+
+}
\ No newline at end of file