IDEMPIERE-6079 fix NPE caused by library ben-manes/caffeine (#2336)

org.adempiere.base/src/org/compiere/util/CCache.java

@@ -369,6 +369,8 @@ public void clear()
 	@Override
 	public boolean containsKey(Object key)
 	{
+		if (key == null)
+			return false;
 		return cache.containsKey(key) || nullList.contains(key);
 	}	//	containsKey
 
@@ -378,6 +380,8 @@ public boolean containsKey(Object key)
 	@Override
 	public boolean containsValue(Object value)
 	{
+		if (value == null)
+			return false;
 		return cache.containsValue(value);
 	}	//	containsValue
 
@@ -397,6 +401,8 @@ public Set<Map.Entry<K,V>> entrySet()
 	@Override
 	public V get(Object key)
 	{
+		if (key == null)
+			return null;
 		V v = cache.get(key);
 		if (v == null)
 			if (nullList.contains(key))

org.idempiere.test/src/org/idempiere/test/performance/CacheTest.java

@@ -24,6 +24,7 @@
  **********************************************************************/
 package org.idempiere.test.performance;
 
+import static org.assertj.core.api.Assertions.assertThatNoException;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -946,4 +947,16 @@ public void testExpire() {
 
 		CacheMgt.get().unregister(cache);
 	}
+
+	@Test
+	public void testNullKey() {
+		CCache<String, String> testCache = new CCache<String, String>(null, "Test_Cache", 10, 60, false);
+		assertThatNoException().isThrownBy(() -> testCache.get(null));
+		assertThatNoException().isThrownBy(() -> testCache.containsKey(null));
+		assertThatNoException().isThrownBy(() -> testCache.containsValue(null));
+		assertFalse(testCache.containsValue(null));
+		testCache.put("TestNull", null);
+		assertFalse(testCache.containsValue(null)); // still false because null is an unknown value
+	}
+
 }