diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ByteStorage.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ByteStorage.java
index 6795079aa..f8043c18c 100644
--- a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ByteStorage.java
+++ b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ByteStorage.java
@@ -8,8 +8,8 @@
 
 import de.hpi.swa.trufflesqueak.util.UnsafeUtils;
 
-public final class ByteStorage extends NativeObjectStorage {
-    final byte[] storage;
+final class ByteStorage extends NativeObjectStorage {
+    private final byte[] storage;
 
     public ByteStorage(final byte[] storage) {
         this.storage = storage;
diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/IntStorage.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/IntStorage.java
index b154363fd..1597d2dba 100644
--- a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/IntStorage.java
+++ b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/IntStorage.java
@@ -8,8 +8,8 @@
 
 import de.hpi.swa.trufflesqueak.util.UnsafeUtils;
 
-public final class IntStorage extends NativeObjectStorage {
-    final int[] storage;
+final class IntStorage extends NativeObjectStorage {
+    private final int[] storage;
 
     public IntStorage(final int[] storage) {
         this.storage = storage;
diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/LongStorage.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/LongStorage.java
index 8184c1615..779d5cf43 100644
--- a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/LongStorage.java
+++ b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/LongStorage.java
@@ -8,8 +8,8 @@
 
 import de.hpi.swa.trufflesqueak.util.UnsafeUtils;
 
-public final class LongStorage extends NativeObjectStorage {
-    final long[] storage;
+final class LongStorage extends NativeObjectStorage {
+    private final long[] storage;
 
     public LongStorage(final long[] storage) {
         this.storage = storage;
diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ShortStorage.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ShortStorage.java
index 9323e7ad8..06f3edafb 100644
--- a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ShortStorage.java
+++ b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/plugins/ffi/wrappers/ShortStorage.java
@@ -8,8 +8,8 @@
 
 import de.hpi.swa.trufflesqueak.util.UnsafeUtils;
 
-public final class ShortStorage extends NativeObjectStorage {
-    final short[] storage;
+final class ShortStorage extends NativeObjectStorage {
+    private final short[] storage;
 
     public ShortStorage(final short[] storage) {
         this.storage = storage;