diff --git a/src/main/java/org/ids_mannheim/FoldedEntry.java b/src/main/java/org/ids_mannheim/FoldedEntry.java
index 68759f3..5a43746 100644
--- a/src/main/java/org/ids_mannheim/FoldedEntry.java
+++ b/src/main/java/org/ids_mannheim/FoldedEntry.java
@@ -3,8 +3,6 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicIntegerArray;
-import java.util.concurrent.atomic.AtomicLong;
-import java.util.concurrent.atomic.LongAdder;
 import java.util.stream.IntStream;
 
 public class FoldedEntry implements Comparable<FoldedEntry> {
diff --git a/src/main/java/org/ids_mannheim/SlidingWindowQueue.java b/src/main/java/org/ids_mannheim/SlidingWindowQueue.java
index a0a2cf8..93acd58 100644
--- a/src/main/java/org/ids_mannheim/SlidingWindowQueue.java
+++ b/src/main/java/org/ids_mannheim/SlidingWindowQueue.java
@@ -16,13 +16,12 @@
         this.flush = flush;
     }
 
-    public boolean add(String k) {
+    public void add(String k) {
         boolean r = super.add(k);
         if (size() == maxSize) {
             this.flush.accept(String.join("\t", this));
             remove(0);
         }
-        return r;
     }
 
     public void reset(int fold) {