From c791bdf1dca3a17ecee3872a4fa2c30762229ea6 Mon Sep 17 00:00:00 2001
From: Tomasz Lelek <tomasz.lelek@allegrogroup.com>
Date: Sun, 5 Feb 2017 12:56:09 +0100
Subject: [PATCH 1/3] BAEL-672 test for weakHashMap

---
 core-java/pom.xml                             |  7 +++
 .../baeldung/weakhashmap/WeakHashMapTest.java | 48 +++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java

diff --git a/core-java/pom.xml b/core-java/pom.xml
index 85afee2968..5c91150941 100644
--- a/core-java/pom.xml
+++ b/core-java/pom.xml
@@ -154,6 +154,12 @@
             <version>${mockito.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.jayway.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${avaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
 
         <dependency>
             <groupId>commons-codec</groupId>
@@ -371,6 +377,7 @@
         <mockito.version>1.10.19</mockito.version>
         <testng.version>6.10</testng.version>
         <assertj.version>3.6.1</assertj.version>
+        <avaitility.version>1.7.0</avaitility.version>
 
         <!-- maven plugins -->
         <maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
diff --git a/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java b/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
new file mode 100644
index 0000000000..fbeb364ab6
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
@@ -0,0 +1,48 @@
+package com.baeldung.weakhashmap;
+
+
+import org.junit.Test;
+
+import java.util.WeakHashMap;
+import java.util.concurrent.TimeUnit;
+
+import static com.jayway.awaitility.Awaitility.await;
+import static org.junit.Assert.assertTrue;
+
+public class WeakHashMapTest {
+
+    @Test
+    public void givenWeakHashMap_whenCacheValueThatHasNoReferenceToIt_GCShouldReclaimThatObject() {
+        //given
+        WeakHashMap<UniqueImageName, BigImage> map = new WeakHashMap<>();
+        BigImage bigImage = new BigImage("foo");
+        UniqueImageName imageName = new UniqueImageName("name_of_big_image");
+
+        map.put(imageName, bigImage);
+        assertTrue(map.containsKey(imageName));
+
+        //when big image is not in use anymore
+        imageName = null;
+        System.gc();
+
+        //then GC will finally reclaim that object
+        await().atMost(10, TimeUnit.SECONDS).until(map::isEmpty);
+    }
+
+
+    class BigImage {
+        public final String imageId;
+
+        BigImage(String imageId) {
+            this.imageId = imageId;
+        }
+    }
+
+    class UniqueImageName {
+        public final String imageName;
+
+        UniqueImageName(String imageName) {
+            this.imageName = imageName;
+        }
+    }
+}

From 0f59b0d5335bba974afb4915b961e859546b32c2 Mon Sep 17 00:00:00 2001
From: Tomasz Lelek <tomasz.lelek@allegrogroup.com>
Date: Sun, 5 Feb 2017 14:13:45 +0100
Subject: [PATCH 2/3] BAEL-672 proper image id

---
 .../test/java/com/baeldung/weakhashmap/WeakHashMapTest.java   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java b/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
index fbeb364ab6..7b34c6b316 100644
--- a/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
+++ b/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
@@ -15,13 +15,13 @@ public class WeakHashMapTest {
     public void givenWeakHashMap_whenCacheValueThatHasNoReferenceToIt_GCShouldReclaimThatObject() {
         //given
         WeakHashMap<UniqueImageName, BigImage> map = new WeakHashMap<>();
-        BigImage bigImage = new BigImage("foo");
+        BigImage bigImage = new BigImage("image_id");
         UniqueImageName imageName = new UniqueImageName("name_of_big_image");
 
         map.put(imageName, bigImage);
         assertTrue(map.containsKey(imageName));
 
-        //when big image is not in use anymore
+        //when big image key is not reference anywhere
         imageName = null;
         System.gc();
 

From 69bfaa557a654c0c66391cd79a61e988fd9b5147 Mon Sep 17 00:00:00 2001
From: Tomasz Lelek <tomasz.lelek@allegrogroup.com>
Date: Tue, 7 Feb 2017 17:50:11 +0100
Subject: [PATCH 3/3] BAEL-672 test case when one object is still referenced

---
 .../baeldung/weakhashmap/WeakHashMapTest.java | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java b/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
index 7b34c6b316..1c5a261eea 100644
--- a/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
+++ b/core-java/src/test/java/com/baeldung/weakhashmap/WeakHashMapTest.java
@@ -29,6 +29,30 @@ public class WeakHashMapTest {
         await().atMost(10, TimeUnit.SECONDS).until(map::isEmpty);
     }
 
+    @Test
+    public void givenWeakHashMap_whenCacheValueThatHasNoReferenceToIt_GCShouldReclaimThatObjectButLeaveReferencedObject() {
+        //given
+        WeakHashMap<UniqueImageName, BigImage> map = new WeakHashMap<>();
+        BigImage bigImageFirst = new BigImage("foo");
+        UniqueImageName imageNameFirst = new UniqueImageName("name_of_big_image");
+
+        BigImage bigImageSecond = new BigImage("foo_2");
+        UniqueImageName imageNameSecond = new UniqueImageName("name_of_big_image_2");
+
+        map.put(imageNameFirst, bigImageFirst);
+        map.put(imageNameSecond, bigImageSecond);
+        assertTrue(map.containsKey(imageNameFirst));
+        assertTrue(map.containsKey(imageNameSecond));
+
+        //when
+        imageNameFirst = null;
+        System.gc();
+
+        //then
+        await().atMost(10, TimeUnit.SECONDS).until(() -> map.size() == 1);
+        await().atMost(10, TimeUnit.SECONDS).until(() -> map.containsKey(imageNameSecond));
+    }
+
 
     class BigImage {
         public final String imageId;