diff --git a/rs/java/android/renderscript/Allocation.java b/rs/java/android/renderscript/Allocation.java
index 6bcb5b6..37c1c7a 100644
--- a/rs/java/android/renderscript/Allocation.java
+++ b/rs/java/android/renderscript/Allocation.java
@@ -372,6 +372,7 @@
             Log.e(RenderScript.LOG_TAG, "Couldn't invoke registerNativeAllocation:" + e);
             throw new RSRuntimeException("Couldn't invoke registerNativeAllocation:" + e);
         }
+        guard.open("destroy");
     }
 
     Allocation(long id, RenderScript rs, Type t, int usage, MipmapControl mips) {
@@ -1907,6 +1908,7 @@
             if (type.getID(rs) == 0) {
                 throw new RSInvalidStateException("Bad Type");
             }
+            // TODO: What if there is an exception after this? The native allocation would leak.
             long id = rs.nAllocationCreateTyped(type.getID(rs), mips.mID, usage, 0);
             if (id == 0) {
                 throw new RSRuntimeException("Allocation creation failed.");
diff --git a/rs/java/android/renderscript/BaseObj.java b/rs/java/android/renderscript/BaseObj.java
index 1372ab7..f95af16 100644
--- a/rs/java/android/renderscript/BaseObj.java
+++ b/rs/java/android/renderscript/BaseObj.java
@@ -16,6 +16,7 @@
 
 package android.renderscript;
 
+import dalvik.system.CloseGuard;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 /**
@@ -69,6 +70,7 @@
     }
 
     private long mID;
+    final CloseGuard guard = CloseGuard.get();
     private boolean mDestroyed;
     private String mName;
     RenderScript mRS;
@@ -119,6 +121,7 @@
         }
 
         if (shouldDestroy) {
+            guard.close();
             // must include nObjDestroy in the critical section
             ReentrantReadWriteLock.ReadLock rlock = mRS.mRWLock.readLock();
             rlock.lock();
@@ -133,8 +136,14 @@
     }
 
     protected void finalize() throws Throwable {
-        helpDestroy();
-        super.finalize();
+        try {
+            if (guard != null) {
+                guard.warnIfOpen();
+            }
+            helpDestroy();
+        } finally {
+            super.finalize();
+        }
     }
 
     /**
diff --git a/rs/java/android/renderscript/Element.java b/rs/java/android/renderscript/Element.java
index 6efb6d6..50226ac 100644
--- a/rs/java/android/renderscript/Element.java
+++ b/rs/java/android/renderscript/Element.java
@@ -808,6 +808,7 @@
             mSize += mElements[ct].mSize * mArraySizes[ct];
         }
         updateVisibleSubElements();
+        guard.open("destroy");
     }
 
     Element(long id, RenderScript rs, DataType dt, DataKind dk, boolean norm, int size) {
@@ -827,6 +828,7 @@
         mKind = dk;
         mNormalized = norm;
         mVectorSize = size;
+        guard.open("destroy");
     }
 
     Element(long id, RenderScript rs) {
diff --git a/rs/java/android/renderscript/FileA3D.java b/rs/java/android/renderscript/FileA3D.java
index 9d8f162..278d309 100644
--- a/rs/java/android/renderscript/FileA3D.java
+++ b/rs/java/android/renderscript/FileA3D.java
@@ -170,6 +170,7 @@
     FileA3D(long id, RenderScript rs, InputStream stream) {
         super(id, rs);
         mInputStream = stream;
+        guard.open("destroy");
     }
 
     private void initEntries() {
diff --git a/rs/java/android/renderscript/Font.java b/rs/java/android/renderscript/Font.java
index 4318b9d..d5ca31e 100644
--- a/rs/java/android/renderscript/Font.java
+++ b/rs/java/android/renderscript/Font.java
@@ -150,6 +150,7 @@
 
     Font(long id, RenderScript rs) {
         super(id, rs);
+        guard.open("destroy");
     }
 
     /**
diff --git a/rs/java/android/renderscript/Mesh.java b/rs/java/android/renderscript/Mesh.java
index 13c8e1c..9e4f905 100644
--- a/rs/java/android/renderscript/Mesh.java
+++ b/rs/java/android/renderscript/Mesh.java
@@ -91,6 +91,7 @@
 
     Mesh(long id, RenderScript rs) {
         super(id, rs);
+        guard.open("destroy");
     }
 
     /**
diff --git a/rs/java/android/renderscript/Program.java b/rs/java/android/renderscript/Program.java
index 3eb9b75..772021c 100644
--- a/rs/java/android/renderscript/Program.java
+++ b/rs/java/android/renderscript/Program.java
@@ -76,6 +76,7 @@
 
     Program(long id, RenderScript rs) {
         super(id, rs);
+        guard.open("destroy");
     }
 
     /**
diff --git a/rs/java/android/renderscript/Sampler.java b/rs/java/android/renderscript/Sampler.java
index a4edbb5..5c4bae9 100644
--- a/rs/java/android/renderscript/Sampler.java
+++ b/rs/java/android/renderscript/Sampler.java
@@ -51,6 +51,7 @@
 
     Sampler(long id, RenderScript rs) {
         super(id, rs);
+        guard.open("destroy");
     }
 
     /**
diff --git a/rs/java/android/renderscript/Script.java b/rs/java/android/renderscript/Script.java
index 84f980d..5b009a6 100644
--- a/rs/java/android/renderscript/Script.java
+++ b/rs/java/android/renderscript/Script.java
@@ -41,6 +41,7 @@
             mScript = s;
             mSlot = slot;
             mSig = sig;
+            guard.open("destroy");
         }
     }
 
@@ -118,6 +119,7 @@
             super(id, rs);
             mScript = s;
             mSlot = slot;
+            guard.open("destroy");
         }
     }
 
@@ -358,6 +360,19 @@
         super(id, rs);
 
         mInIdsBuffer = new long[1];
+
+        /* The constructors for the derived classes (including ScriptIntrinsic
+         * derived classes and ScriptC derived classes generated by Slang
+         * reflection) seem to be simple enough, so we just put the guard.open()
+         * call here, rather than in the end of the constructor for the derived
+         * class. This, of course, assumes the derived constructor would not
+         * throw any exception after calling this constructor.
+         *
+         * If new derived classes are added with more complicated constructors
+         * that throw exceptions, this call has to be (duplicated and) moved
+         * to the end of each derived class constructor.
+         */
+        guard.open("destroy");
     }
 
     /**
diff --git a/rs/java/android/renderscript/ScriptGroup.java b/rs/java/android/renderscript/ScriptGroup.java
index 9357c3bb..219f16b 100644
--- a/rs/java/android/renderscript/ScriptGroup.java
+++ b/rs/java/android/renderscript/ScriptGroup.java
@@ -148,6 +148,8 @@
                                         fieldIDs, values, sizes, depClosures, depFieldIDs);
 
             setID(id);
+
+            guard.open("destroy");
         }
 
         Closure(RenderScript rs, Script.InvokeID invokeID,
@@ -181,6 +183,8 @@
                                               values, sizes);
 
             setID(id);
+
+            guard.open("destroy");
         }
 
         private void retrieveValueAndDependenceInfo(RenderScript rs,
@@ -382,6 +386,7 @@
 
     ScriptGroup(long id, RenderScript rs) {
         super(id, rs);
+        guard.open("destroy");
     }
 
     ScriptGroup(RenderScript rs, String name, List<Closure> closures,
@@ -398,6 +403,7 @@
         }
         long id = rs.nScriptGroup2Create(name, RenderScript.getCachePath(), closureIDs);
         setID(id);
+        guard.open("destroy");
     }
 
     /**
diff --git a/rs/java/android/renderscript/Type.java b/rs/java/android/renderscript/Type.java
index dc23785..9252898 100644
--- a/rs/java/android/renderscript/Type.java
+++ b/rs/java/android/renderscript/Type.java
@@ -227,6 +227,7 @@
 
     Type(long id, RenderScript rs) {
         super(id, rs);
+        guard.open("destroy");
     }
 
     @Override