Prevent MemoryUsage.sizeOf from failing if JOL fails

Author: DarthMax

memory-usage/src/main/java/org/neo4j/gds/mem/MemoryUsage.java

@@ -298,7 +298,12 @@ public static long sizeOf(Object thing) {
         if (!VmInfoHolder.VM_INFO_AVAILABLE) {
             return -1L;
         }
-        return new GraphWalker().walk(thing).totalSize();
+
+        try {
+            return new GraphWalker().walk(thing).totalSize();
+        } catch (RuntimeException e) {
+            return -1;
+        }
     }
 
     /**

memory-usage/src/test/java/org/neo4j/gds/mem/MemoryUsageTest.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) "Neo4j"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.gds.mem;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThatCode;
+
+class MemoryUsageTest {
+
+    @Test
+    void ofShouldNotFailIfJOLFails() {
+        assertThatCode(() -> MemoryUsage.sizeOf(new JOLMightFail())).doesNotThrowAnyException();
+    }
+
+    // The nested recursive ThreadLocal causes JOL to be unable to access some attributes of the class on the ZULU JVM
+    private static final class JOLMightFail {
+        private final ThreadLocal<JOLMightFail> threadLocal;
+
+        private JOLMightFail() {threadLocal = ThreadLocal.withInitial(() -> this);}
+
+        ThreadLocal<JOLMightFail> getThreadLocal() {
+            return threadLocal;
+        }
+    }
+
+}