--- a/jdk/src/share/classes/com/sun/demo/jvmti/hprof/Tracker.java	Fri Jul 19 12:14:34 2013 +0900
+++ b/jdk/src/share/classes/com/sun/demo/jvmti/hprof/Tracker.java	Fri Jul 19 13:35:01 2013 +0200
@@ -53,7 +53,10 @@
 
     public static void ObjectInit(Object obj)
     {
-        if ( engaged != 0 ) {
+        if ( engaged != 0) {
+            if (obj == null) {
+                throw new IllegalArgumentException("Null object.");
+            }
             nativeObjectInit(Thread.currentThread(), obj);
         }
     }
@@ -66,7 +69,10 @@
 
     public static void NewArray(Object obj)
     {
-        if ( engaged != 0 ) {
+        if ( engaged != 0) {
+            if (obj == null) {
+                throw new IllegalArgumentException("Null object.");
+            }
             nativeNewArray(Thread.currentThread(), obj);
         }
     }
@@ -82,6 +88,14 @@
     public static void CallSite(int cnum, int mnum)
     {
         if ( engaged != 0 ) {
+            if (cnum < 0) {
+                throw new IllegalArgumentException("Negative class index");
+            }
+
+            if (mnum < 0) {
+                throw new IllegalArgumentException("Negative method index");
+            }
+
             nativeCallSite(Thread.currentThread(), cnum, mnum);
         }
     }
@@ -95,6 +109,14 @@
     public static void ReturnSite(int cnum, int mnum)
     {
         if ( engaged != 0 ) {
+            if (cnum < 0) {
+                throw new IllegalArgumentException("Negative class index");
+            }
+
+            if (mnum < 0) {
+                throw new IllegalArgumentException("Negative method index");
+            }
+
             nativeReturnSite(Thread.currentThread(), cnum, mnum);
         }
     }

--- a/jdk/src/share/demo/jvmti/hprof/hprof_class.c	Fri Jul 19 12:14:34 2013 +0900
+++ b/jdk/src/share/demo/jvmti/hprof/hprof_class.c	Fri Jul 19 13:35:01 2013 +0200
@@ -527,7 +527,12 @@
     jmethodID  method;
 
     info = get_info(index);
-    HPROF_ASSERT(mnum < info->method_count);
+    if (mnum >= info->method_count) {
+        jclass newExcCls = (*env)->FindClass(env, "java/lang/IllegalArgumentException");
+        (*env)->ThrowNew(env, newExcCls, "Illegal mnum");
+
+        return NULL;
+    }
     method = info->method[mnum].method_id;
     if ( method == NULL ) {
         char * name;
@@ -535,7 +540,12 @@
         jclass clazz;
 
         name  = (char *)string_get(info->method[mnum].name_index);
-        HPROF_ASSERT(name!=NULL);
+        if (name==NULL) {
+            jclass newExcCls = (*env)->FindClass(env, "java/lang/IllegalArgumentException");
+            (*env)->ThrowNew(env, newExcCls, "Name not found");
+
+            return NULL;
+        }
         sig   = (char *)string_get(info->method[mnum].sig_index);
         HPROF_ASSERT(sig!=NULL);
         clazz = class_get_class(env, index);

--- a/jdk/src/share/demo/jvmti/hprof/hprof_event.c	Fri Jul 19 12:14:34 2013 +0900
+++ b/jdk/src/share/demo/jvmti/hprof/hprof_event.c	Fri Jul 19 13:35:01 2013 +0200
@@ -195,7 +195,12 @@
 
     HPROF_ASSERT(env!=NULL);
     HPROF_ASSERT(thread!=NULL);
-    HPROF_ASSERT(cnum!=0 && cnum!=gdata->tracker_cnum);
+    if (cnum == 0 || cnum == gdata->tracker_cnum) {
+        jclass newExcCls = (*env)->FindClass(env, "java/lang/IllegalArgumentException");
+        (*env)->ThrowNew(env, newExcCls, "Illegal cnum.");
+
+        return;
+    }
 
     /* Prevent recursion into any BCI function for this thread (pstatus). */
     if ( tls_get_tracker_status(env, thread, JNI_FALSE,
@@ -204,8 +209,10 @@
 
         (*pstatus) = 1;
         method      = class_get_methodID(env, cnum, mnum);
-        HPROF_ASSERT(method!=NULL);
-        tls_push_method(tls_index, method);
+        if (method != NULL) {
+            tls_push_method(tls_index, method);
+        }
+
         (*pstatus) = 0;
     }
 }
@@ -248,7 +255,13 @@
 
     HPROF_ASSERT(env!=NULL);
     HPROF_ASSERT(thread!=NULL);
-    HPROF_ASSERT(cnum!=0 && cnum!=gdata->tracker_cnum);
+
+    if (cnum == 0 || cnum == gdata->tracker_cnum) {
+        jclass newExcCls = (*env)->FindClass(env, "java/lang/IllegalArgumentException");
+        (*env)->ThrowNew(env, newExcCls, "Illegal cnum.");
+
+        return;
+    }
 
     /* Prevent recursion into any BCI function for this thread (pstatus). */
     if ( tls_get_tracker_status(env, thread, JNI_FALSE,
@@ -257,8 +270,10 @@
 
         (*pstatus) = 1;
         method      = class_get_methodID(env, cnum, mnum);
-        HPROF_ASSERT(method!=NULL);
-        tls_pop_method(tls_index, thread, method);
+        if (method != NULL) {
+            tls_pop_method(tls_index, thread, method);
+        }
+
         (*pstatus) = 0;
     }
 }