cache

diff --git a/src/main/java/br/ufrgs/inf/prosoft/cache/MultiCache.java b/src/main/java/br/ufrgs/inf/prosoft/cache/MultiCache.java
index ab1b242..702a450 100644
--- a/src/main/java/br/ufrgs/inf/prosoft/cache/MultiCache.java
+++ b/src/main/java/br/ufrgs/inf/prosoft/cache/MultiCache.java
@@ -29,6 +29,7 @@ public class MultiCache<K, V> implements Cache<K, V> {
     private final HashMap<K, V> map;
     private final ConcurrentHashMap<Optional<K>, Long> keyHasTTL;
     private final CachePerformance cachePerformance;
+    private ScheduledExecutorService batchEntriesInvalidator;
 
     public MultiCache() {
         this(new CachePerformance());
@@ -42,15 +43,6 @@ public class MultiCache<K, V> implements Cache<K, V> {
         this.cachePerformance = cachingPerformance;
         this.map = new HashMap<>();
         this.keyHasTTL = new ConcurrentHashMap<>();
-
-        ScheduledExecutorService batchEntriesInvalidator = Executors.newScheduledThreadPool(1);
-        batchEntriesInvalidator.scheduleAtFixedRate(() -> {
-            this.keyHasTTL.forEach((key, value) -> {
-                if (!isValid(key.orElse(null))) {
-                    invalidate(key.orElse(null));
-                }
-            });
-        }, 10, 10, TimeUnit.SECONDS);
     }
 
     public CachePerformance getCachePerformance() {
@@ -61,6 +53,20 @@ public class MultiCache<K, V> implements Cache<K, V> {
     public void put(K key, V value, long timeToLive) {
         put(key, value);
         this.keyHasTTL.put(Optional.ofNullable(key), System.currentTimeMillis() + timeToLive);
+        if (batchEntriesInvalidator == null) {
+            batchEntriesInvalidator = Executors.newScheduledThreadPool(0);
+            batchEntriesInvalidator.scheduleAtFixedRate(() -> {
+                this.keyHasTTL.forEach((k, v) -> {
+                    if (!isValid(k.orElse(null))) {
+                        invalidate(k.orElse(null));
+                    }
+                });
+                if (this.keyHasTTL.isEmpty()) {
+                    this.batchEntriesInvalidator.shutdown();
+                    this.batchEntriesInvalidator = null;
+                }
+            }, 10, 10, TimeUnit.SECONDS);
+        }
     }
 
     @Override