Avoid NPE when setting additionalProperties path

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/rules/AdditionalPropertiesRule.java

@@ -105,7 +105,7 @@ public JDefinedClass apply(String nodeName, JsonNode node, JsonNode parent, JDef
         JType propertyType;
         if (node != null && node.size() != 0) {
             String pathToAdditionalProperties;
-            if (schema.getId().getFragment() == null) {
+            if (schema.getId() == null || schema.getId().getFragment() == null) {
                 pathToAdditionalProperties = "#/additionalProperties";
             } else {
                 pathToAdditionalProperties = "#" + schema.getId().getFragment() + "/additionalProperties";

jsonschema2pojo-core/src/test/java/org/jsonschema2pojo/rules/AdditionalPropertiesRuleTest.java

@@ -0,0 +1,52 @@
+/**
+ * Copyright © 2010-2020 Nokia
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jsonschema2pojo.rules;
+
+import static org.junit.Assert.assertEquals;
+
+import org.jsonschema2pojo.Schema;
+import org.junit.Test;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.sun.codemodel.JClass;
+import com.sun.codemodel.JCodeModel;
+import com.sun.codemodel.JDefinedClass;
+import com.sun.codemodel.JMethod;
+import com.sun.codemodel.JType;
+
+public class AdditionalPropertiesRuleTest {
+
+    @Test
+    public void testSchemaWithNullURI() throws Exception {
+        ObjectMapper mapper = new ObjectMapper();
+        ObjectNode node = (ObjectNode) mapper
+                .readTree("{\"type\":\"integer\",\"maximum\":9}");
+        ObjectNode parent = (ObjectNode) mapper
+                .readTree("{\"type\":\"object\",\"additionalProperties\":{\"type\":\"integer\",\"maximum\":9}}");
+        Schema schema = new Schema(null, parent, null);
+
+        JDefinedClass jclass = new JCodeModel()._class("org.jsonschema2pojo.rules.ExampleClass");
+        AdditionalPropertiesRule rule = new AdditionalPropertiesRule(new RuleFactory());
+
+        JDefinedClass result = rule.apply("node", node, parent, jclass, schema);
+        JMethod method = result.getMethod("getAdditionalProperties", new JType[0]);
+        JClass returnType = (JClass) method.type();
+        assertEquals("Map<String,Integer>", returnType.name());
+    }
+
+}