fix code

hutool-cache/src/main/java/cn/hutool/cache/Cache.java

@@ -83,14 +83,6 @@ public interface Cache<K, V> extends Iterable<V>, Serializable {
 	 */
 	V get(K key, boolean isUpdateLastAccess);
 
-	/**
-	 * 返回缓存迭代器
-	 * 
-	 * @return 缓存迭代器
-	 */
-	@Override
-	Iterator<V> iterator();
-
 	/**
 	 * 返回包含键和值得迭代器
 	 * 

hutool-cache/src/main/java/cn/hutool/cache/file/LFUFileCache.java

@@ -45,20 +45,19 @@ public class LFUFileCache extends AbstractFileCache{
 
 	@Override
 	protected Cache<File, byte[]> initCache() {
-		Cache<File, byte[]> cache = new LFUCache<File, byte[]>(this.capacity, this.timeout) {
-			private static final long serialVersionUID = 1L;
-			
+		return new LFUCache<File, byte[]>(LFUFileCache.this.capacity, LFUFileCache.this.timeout) {
+			private static final long serialVersionUID1 = 1L;
+
 			@Override
 			public boolean isFull() {
 				return LFUFileCache.this.usedSize > this.capacity;
 			}
-			
+
 			@Override
 			protected void onRemove(File key, byte[] cachedObject) {
 				usedSize -= cachedObject.length;
 			}
 		};
-		return cache;
 	}
 
 }

hutool-cache/src/main/java/cn/hutool/cache/file/LRUFileCache.java

@@ -45,20 +45,19 @@ public class LRUFileCache extends AbstractFileCache{
 
 	@Override
 	protected Cache<File, byte[]> initCache() {
-		Cache<File, byte[]> cache = new LRUCache<File, byte[]>(this.capacity, super.timeout) {
-			private static final long serialVersionUID = 1L;
-			
+		return new LRUCache<File, byte[]>(LRUFileCache.this.capacity, super.timeout) {
+			private static final long serialVersionUID1 = 1L;
+
 			@Override
 			public boolean isFull() {
 				return LRUFileCache.this.usedSize > this.capacity;
 			}
-			
+
 			@Override
 			protected void onRemove(File key, byte[] cachedObject) {
 				usedSize -= cachedObject.length;
 			}
 		};
-		return cache;
 	}
 
 }

hutool-cache/src/main/java/cn/hutool/cache/impl/CacheObj.java

@@ -20,7 +20,7 @@ public class CacheObj<K, V> implements Serializable{
 	/** 访问次数 */
 	protected long accessCount;
 	/** 对象存活时长，0表示永久存活*/
-	private long ttl;
+	private final long ttl;
 	
 	/**
 	 * 构造

hutool-cache/src/main/java/cn/hutool/cache/impl/CacheObjIterator.java

@@ -23,7 +23,6 @@ public class CacheObjIterator<K, V> implements Iterator<CacheObj<K, V>>, Seriali
 	 * 构造
 	 * 
 	 * @param iterator 原{@link Iterator}
-	 * @param readLock 读锁
 	 */
 	CacheObjIterator(Iterator<CacheObj<K, V>> iterator) {
 		this.iterator = iterator;

hutool-cache/src/main/java/cn/hutool/cache/impl/CacheValuesIterator.java

@@ -17,7 +17,6 @@ public class CacheValuesIterator<V> implements Iterator<V>, Serializable {
 	/**
 	 * 构造
 	 * @param iterator 原{@link CacheObjIterator}
-	 * @param readLock 读锁
 	 */
 	CacheValuesIterator(CacheObjIterator<?, V> iterator) {
 		this.cacheObjIter = iterator;

hutool-cache/src/test/java/cn/hutool/cache/test/CacheTest.java

@@ -1,14 +1,12 @@
 package cn.hutool.cache.test;
 
-import org.junit.Assert;
-import org.junit.Test;
-
 import cn.hutool.cache.Cache;
 import cn.hutool.cache.CacheUtil;
 import cn.hutool.cache.impl.TimedCache;
 import cn.hutool.core.date.DateUnit;
-import cn.hutool.core.lang.func.Func0;
 import cn.hutool.core.thread.ThreadUtil;
+import org.junit.Assert;
+import org.junit.Test;
 
 /**
  * 缓存测试用例
@@ -27,7 +25,7 @@ public class CacheTest {
 		
 		//由于缓存容量只有3，当加入第四个元素的时候，根据FIFO规则，最先放入的对象将被移除
 		String value1 = fifoCache.get("key1");
-		Assert.assertTrue(null == value1);
+		Assert.assertNull(value1);
 	}
 	
 	@Test
@@ -44,9 +42,9 @@ public class CacheTest {
 		String value1 = lfuCache.get("key1");
 		String value2 = lfuCache.get("key2");
 		String value3 = lfuCache.get("key3");
-		Assert.assertTrue(null != value1);
-		Assert.assertTrue(null == value2);
-		Assert.assertTrue(null == value3);
+		Assert.assertNotNull(value1);
+		Assert.assertNull(value2);
+		Assert.assertNull(value3);
 	}
 	
 	@Test
@@ -84,21 +82,15 @@ public class CacheTest {
 		
 		//5毫秒后由于value2设置了5毫秒过期，因此只有value2被保留下来
 		String value1 = timedCache.get("key1");
-		Assert.assertTrue(null == value1);
+		Assert.assertNull(value1);
 		String value2 = timedCache.get("key2");
 		Assert.assertEquals("value2", value2);
 		
 		//5毫秒后，由于设置了默认过期，key3只被保留4毫秒，因此为null
 		String value3 = timedCache.get("key3");
-		Assert.assertTrue(null == value3);
+		Assert.assertNull(value3);
 		
-		String value3Supplier = timedCache.get("key3", new Func0<String>() {
-			
-			@Override
-			public String call() throws Exception {
-				return "Default supplier";
-			}
-		});
+		String value3Supplier = timedCache.get("key3", () -> "Default supplier");
 		Assert.assertEquals("Default supplier", value3Supplier);
 		
 		// 永不过期