fixes #273 make the getInstance() deprecated

Author: stevehu

src/main/java/com/networknt/schema/JsonSchemaFactory.java

@@ -188,6 +188,14 @@ static Builder builder() {
         return new Builder();
     }
 
+    /**
+     * @deprecated
+     * This is a method that is kept to ensure backward compatible. You shouldn't use it anymore.
+     * Please specify the draft version when get an instance.
+     *
+     * @return JsonSchemaFactory
+     */
+    @Deprecated
     public static JsonSchemaFactory getInstance() {
         return getInstance(SpecVersion.VersionFlag.V4);
     }

src/test/java/com/networknt/schema/V4JsonSchemaTest.java

@@ -39,7 +39,7 @@
 
 public class V4JsonSchemaTest {
     protected ObjectMapper mapper = new ObjectMapper();
-    protected JsonSchemaFactory validatorFactory = JsonSchemaFactory.builder(JsonSchemaFactory.getInstance()).objectMapper(mapper).build();
+    protected JsonSchemaFactory validatorFactory = JsonSchemaFactory.builder(JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V4)).objectMapper(mapper).build();
     protected static Undertow server = null;
 
     public V4JsonSchemaTest() {