diff --git a/src/main/java/de/kosit/validationtool/impl/ConversionService.java b/src/main/java/de/kosit/validationtool/impl/ConversionService.java
index 96d219a..787e6e5 100644
--- a/src/main/java/de/kosit/validationtool/impl/ConversionService.java
+++ b/src/main/java/de/kosit/validationtool/impl/ConversionService.java
@@ -53,7 +53,7 @@ public class ConversionService {
     /**
      * Exception while serializing/deserializing with jaxb.
      */
-    public class ConversionException extends RuntimeException {
+    public static class ConversionException extends RuntimeException {
 
         private static final long serialVersionUID = 7950889507519996452L;
 
diff --git a/src/test/java/de/kosit/validationtool/impl/xml/BaseResolverConfigurationTest.java b/src/test/java/de/kosit/validationtool/impl/xml/BaseResolverConfigurationTest.java
index 76e2d86..687af9c 100644
--- a/src/test/java/de/kosit/validationtool/impl/xml/BaseResolverConfigurationTest.java
+++ b/src/test/java/de/kosit/validationtool/impl/xml/BaseResolverConfigurationTest.java
@@ -36,7 +36,7 @@ import static org.mockito.Mockito.*;
 public class BaseResolverConfigurationTest {
 
     @RequiredArgsConstructor
-    private class TestResolvingStrategy extends StrictRelativeResolvingStrategy {
+    private static class TestResolvingStrategy extends StrictRelativeResolvingStrategy {
 
         void setInternalProperty(final SchemaFactory factory, final boolean lenient) {
             allowExternalSchema(factory, lenient, NOT_EXISTING_SCHEME);