Ensure disposed memory is removed from Memory#allocatedMemory map

Closes: java-native-access#697

CHANGES.md

@@ -85,6 +85,7 @@ Bug Fixes
 * [#696](https://github.com/java-native-access/jna/issues/696): COMLateBindingObject.getAutomationProperty method that takes iDispatch parameter doesn't use it - [@matthiasblaesing](https://github.com/matthiasblaesing).
 * [#664](https://github.com/java-native-access/jna/issues/664): Prevent premature GC of Pointer and Function objects by passing whole object into JNI call in addition to the raw pointer value - [@matthiasblaesing](https://github.com/matthiasblaesing).
 * [#669](https://github.com/java-native-access/jna/pull/669): Ensure XSI-compliant strerror_r is used, to prevent corrupted error messages on linux - [@DavidKeller](https://github.com/DavidKeller).
+* [#697](https://github.com/java-native-access/jna/issues/697): Ensure disposed memory is removed from Memory#allocatedMemory map - [@matthiasblaesing](https://github.com/matthiasblaesing).
 
 Release 4.2.1
 =============

src/com/sun/jna/Memory.java

@@ -180,8 +180,8 @@ protected synchronized void dispose() {
         try {
             free(peer);
         } finally {
-            peer = 0;
             allocatedMemory.remove(this);
+            peer = 0;
         }
     }
 

test/com/sun/jna/MemoryTest.java

@@ -14,7 +14,9 @@
 
 import java.lang.ref.Reference;
 import java.lang.ref.WeakReference;
+import java.lang.reflect.Field;
 import java.nio.ByteBuffer;
+import java.util.Map;
 
 import junit.framework.TestCase;
 
@@ -175,6 +177,25 @@ public void testDump() {
             "[08090a0b]" + ls +
             "[0c0d0e]" + ls, m.dump());
     }
+
+    public void testRemoveAllocatedMemoryMap() throws NoSuchFieldException, IllegalArgumentException, IllegalAccessException {
+        // Make sure there are no remaining allocations
+        Memory.disposeAll();
+
+        // get a reference to the allocated memory
+        Field allocatedMemoryField = Memory.class.getDeclaredField("allocatedMemory");
+        allocatedMemoryField.setAccessible(true);
+        Map<Memory, Reference<Memory>> allocatedMemory = (Map<Memory, Reference<Memory>>) allocatedMemoryField.get(null);
+        assertEquals(0, allocatedMemory.size());
+
+        // Test allocation and ensure it is accounted for
+        Memory mem = new Memory(1024);
+        assertEquals(1, allocatedMemory.size());
+
+        // Dispose memory and ensure allocation is removed from allocatedMemory-Map
+        mem.dispose();
+        assertEquals(0, allocatedMemory.size());
+    }
 
     public static void main(String[] args) {
         junit.textui.TestRunner.run(MemoryTest.class);