diff --git a/android/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java b/android/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java
index e4696465d935..dc9b1d3d8bbb 100644
--- a/android/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java
+++ b/android/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java
@@ -18,7 +18,6 @@
 
 import static com.google.common.collect.Lists.newArrayList;
 import static com.google.common.collect.testing.IteratorFeature.MODIFIABLE;
-import static java.util.Collections.emptyList;
 
 import com.google.common.annotations.GwtCompatible;
 import com.google.common.collect.ImmutableList;
diff --git a/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LocalCache.java b/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LocalCache.java
index 0b6fb02d384c..0f195dddd413 100644
--- a/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LocalCache.java
+++ b/guava-gwt/src-super/com/google/common/cache/super/com/google/common/cache/LocalCache.java
@@ -349,10 +349,12 @@ public long getWriteTimestamp() {
       return writeTimestamp;
     }
 
+    @Override
     public boolean equals(Object o) {
       return value.equals(o);
     }
 
+    @Override
     public int hashCode() {
       return value.hashCode();
     }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableCollection.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableCollection.java
index b12b85e678de..d9c1d0bc6391 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableCollection.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableCollection.java
@@ -48,6 +48,7 @@ public boolean containsAll(Collection<?> targets) {
     return delegate.containsAll(targets);
   }
 
+  @Override
   public int size() {
     return delegate.size();
   }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableList.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableList.java
index 7d95f7153254..64fe66ea6459 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableList.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableList.java
@@ -31,18 +31,22 @@ abstract class ForwardingImmutableList<E> extends ImmutableList<E> {
 
   abstract List<E> delegateList();
 
+  @Override
   public int indexOf(@Nullable Object object) {
     return delegateList().indexOf(object);
   }
 
+  @Override
   public int lastIndexOf(@Nullable Object object) {
     return delegateList().lastIndexOf(object);
   }
 
+  @Override
   public E get(int index) {
     return delegateList().get(index);
   }
 
+  @Override
   public ImmutableList<E> subList(int fromIndex, int toIndex) {
     return unsafeDelegateList(delegateList().subList(fromIndex, toIndex));
   }
@@ -79,6 +83,7 @@ public boolean containsAll(Collection<?> targets) {
     return delegateList().containsAll(targets);
   }
 
+  @Override
   public int size() {
     return delegateList().size();
   }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java
index 7f07e1e1dcbf..68ff90ad2b31 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java
@@ -49,22 +49,27 @@ public abstract class ForwardingImmutableMap<K, V> extends ImmutableMap<K, V> {
     this.delegate = Collections.unmodifiableMap(delegate);
   }
 
+  @Override
   boolean isPartialView() {
     return false;
   }
 
+  @Override
   public final boolean isEmpty() {
     return delegate.isEmpty();
   }
 
+  @Override
   public final boolean containsKey(@Nullable Object key) {
     return Maps.safeContainsKey(delegate, key);
   }
 
+  @Override
   public final boolean containsValue(@Nullable Object value) {
     return delegate.containsValue(value);
   }
 
+  @Override
   public @Nullable V get(@Nullable Object key) {
     return (key == null) ? null : Maps.safeGet(delegate, key);
   }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableBiMap.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableBiMap.java
index 4a10bd16f345..767430d66cc4 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableBiMap.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableBiMap.java
@@ -196,6 +196,7 @@ public Builder<K, V> putAll(Iterable<? extends Entry<? extends K, ? extends V>>
     }
 
     @CanIgnoreReturnValue
+    @Override
     public Builder<K, V> orderEntriesByValue(Comparator<? super V> valueComparator) {
       super.orderEntriesByValue(valueComparator);
       return this;
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableCollection.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableCollection.java
index d6f90f2a26bb..7321b00d1960 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableCollection.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableCollection.java
@@ -39,36 +39,45 @@ public abstract class ImmutableCollection<E> extends AbstractCollection<E> imple
 
   ImmutableCollection() {}
 
+  @Override
   public abstract UnmodifiableIterator<E> iterator();
 
+  @Override
   public boolean contains(@Nullable Object object) {
     return object != null && super.contains(object);
   }
 
+  @Override
   public final boolean add(E e) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final boolean remove(@Nullable Object object) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final boolean addAll(Collection<? extends E> newElements) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final boolean removeAll(Collection<?> oldElements) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final boolean removeIf(Predicate<? super E> predicate) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final boolean retainAll(Collection<?> elementsToKeep) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final void clear() {
     throw new UnsupportedOperationException();
   }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableList.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableList.java
index 149035a00a18..a3176d14a12c 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableList.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableList.java
@@ -231,18 +231,22 @@ public int lastIndexOf(@Nullable Object object) {
     return (object == null) ? -1 : Lists.lastIndexOfImpl(this, object);
   }
 
+  @Override
   public final boolean addAll(int index, Collection<? extends E> newElements) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final E set(int index, E element) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final void add(int index, E element) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final E remove(int index) {
     throw new UnsupportedOperationException();
   }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableMap.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableMap.java
index 093848b21394..a474a915011d 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableMap.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableMap.java
@@ -402,18 +402,22 @@ public static <K, V> ImmutableMap<K, V> copyOf(
 
   abstract boolean isPartialView();
 
+  @Override
   public final @Nullable V put(K k, V v) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final @Nullable V remove(Object o) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final void putAll(Map<? extends K, ? extends V> map) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public final void clear() {
     throw new UnsupportedOperationException();
   }
@@ -435,6 +439,7 @@ public boolean containsValue(@Nullable Object value) {
 
   private transient @Nullable ImmutableSet<Entry<K, V>> cachedEntrySet = null;
 
+  @Override
   public final ImmutableSet<Entry<K, V>> entrySet() {
     if (cachedEntrySet != null) {
       return cachedEntrySet;
@@ -446,6 +451,7 @@ public final ImmutableSet<Entry<K, V>> entrySet() {
 
   private transient @Nullable ImmutableSet<K> cachedKeySet = null;
 
+  @Override
   public ImmutableSet<K> keySet() {
     if (cachedKeySet != null) {
       return cachedKeySet;
@@ -478,6 +484,7 @@ Spliterator<K> keySpliterator() {
 
   private transient @Nullable ImmutableCollection<V> cachedValues = null;
 
+  @Override
   public ImmutableCollection<V> values() {
     if (cachedValues != null) {
       return cachedValues;
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSet.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSet.java
index 8ff68390b5ce..8953de2573eb 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSet.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSet.java
@@ -198,6 +198,7 @@ public ImmutableList<E> asList() {
       }
     }
 
+    @Override
     ImmutableList<E> createAsList() {
       return new RegularImmutableAsList<E>(this, toArray());
     }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java
index dce484fe2209..0a7ad60dfc46 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java
@@ -418,14 +418,17 @@ ImmutableSortedSet<K> createKeySet() {
     return ImmutableSortedSet.copyOf(comparator, sortedDelegate.keySet());
   }
 
+  @Override
   public Comparator<? super K> comparator() {
     return comparator;
   }
 
+  @Override
   public @Nullable K firstKey() {
     return sortedDelegate.firstKey();
   }
 
+  @Override
   public @Nullable K lastKey() {
     return sortedDelegate.lastKey();
   }
@@ -441,6 +444,7 @@ public Comparator<? super K> comparator() {
     return null;
   }
 
+  @Override
   public ImmutableSortedMap<K, V> headMap(K toKey) {
     checkNotNull(toKey);
     return newView(sortedDelegate.headMap(toKey));
@@ -458,6 +462,7 @@ ImmutableSortedMap<K, V> headMap(K toKey, boolean inclusive) {
     return headMap(toKey);
   }
 
+  @Override
   public ImmutableSortedMap<K, V> subMap(K fromKey, K toKey) {
     checkNotNull(fromKey);
     checkNotNull(toKey);
@@ -472,6 +477,7 @@ ImmutableSortedMap<K, V> subMap(K fromKey, boolean fromInclusive, K toKey, boole
     return tailMap(fromKey, fromInclusive).headMap(toKey, toInclusive);
   }
 
+  @Override
   public ImmutableSortedMap<K, V> tailMap(K fromKey) {
     checkNotNull(fromKey);
     return newView(sortedDelegate.tailMap(fromKey));
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java
index 11ed51e6492f..56ab76289e17 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java
@@ -256,6 +256,7 @@ static <E> ImmutableSortedSet<E> unsafeDelegateSortedSet(
     this.sortedDelegate = Collections.unmodifiableSortedSet(sortedDelegate);
   }
 
+  @Override
   public Comparator<? super E> comparator() {
     return sortedDelegate.comparator();
   }
@@ -310,10 +311,12 @@ public boolean containsAll(Collection<?> targets) {
     }
   }
 
+  @Override
   public E first() {
     return sortedDelegate.first();
   }
 
+  @Override
   public ImmutableSortedSet<E> headSet(E toElement) {
     checkNotNull(toElement);
     try {
@@ -357,10 +360,12 @@ public ImmutableSortedSet<E> headSet(E toElement, boolean inclusive) {
     return headSet(toElement);
   }
 
+  @Override
   public E last() {
     return sortedDelegate.last();
   }
 
+  @Override
   public ImmutableSortedSet<E> subSet(E fromElement, E toElement) {
     return subSet(fromElement, true, toElement, false);
   }
@@ -377,6 +382,7 @@ ImmutableSortedSet<E> subSet(
     return tailSet(fromElement, fromInclusive).headSet(toElement, toInclusive);
   }
 
+  @Override
   public ImmutableSortedSet<E> tailSet(E fromElement) {
     checkNotNull(fromElement);
     try {
diff --git a/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java b/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java
index e4696465d935..dc9b1d3d8bbb 100644
--- a/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java
+++ b/guava-testlib/test/com/google/common/collect/testing/IteratorTesterTest.java
@@ -18,7 +18,6 @@
 
 import static com.google.common.collect.Lists.newArrayList;
 import static com.google.common.collect.testing.IteratorFeature.MODIFIABLE;
-import static java.util.Collections.emptyList;
 
 import com.google.common.annotations.GwtCompatible;
 import com.google.common.collect.ImmutableList;