Fix #1872 (#1923)

Author: mcasasola

release-notes/VERSION

@@ -4,6 +4,12 @@ Project: jackson-databind
 === Releases ===
 ------------------------------------------------------------------------
 
+2.7.9.3 (not yet released)
+
+#1872 `NullPointerException` in `SubTypeValidator.validateSubType` when
+  validating Spring interface
+ (reported by Rob W)
+
 2.7.9.2 (20-Dec-2017)
 
 #1607: @JsonIdentityReference not used when setup on class only

src/main/java/com/fasterxml/jackson/databind/jsontype/impl/SubTypeValidator.java

@@ -79,8 +79,9 @@ public void validateSubType(DeserializationContext ctxt, JavaType type) throws J
 
             // 18-Dec-2017, tatu: As per [databind#1855], need bit more sophisticated handling
             //    for some Spring framework types
-            if (full.startsWith(PREFIX_STRING)) {
-                for (Class<?> cls = raw; cls != Object.class; cls = cls.getSuperclass()) {
+            // 05-Jan-2017, tatu: ... also, only applies to classes, not interfaces
+            if (!raw.isInterface() && full.startsWith(PREFIX_STRING)) {
+                for (Class<?> cls = raw; (cls != null) && (cls != Object.class); cls = cls.getSuperclass()){
                     String name = cls.getSimpleName();
                     // looking for "AbstractBeanFactoryPointcutAdvisor" but no point to allow any is there?
                     if ("AbstractPointcutAdvisor".equals(name)

src/test/java/com/fasterxml/jackson/databind/interop/IllegalTypesCheckTest.java

@@ -2,10 +2,14 @@
 
 import org.springframework.jacksontest.BogusApplicationContext;
 import org.springframework.jacksontest.BogusPointcutAdvisor;
+import org.springframework.jacksontest.GrantedAuthority;
 
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.fasterxml.jackson.databind.*;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Test case(s) to guard against handling of types that are illegal to handle
  * due to security constraints.
@@ -22,6 +26,10 @@ static class PolyWrapper {
                 include = JsonTypeInfo.As.WRAPPER_ARRAY)
         public Object v;
     }
+
+    static class Authentication1872 {
+         public List<GrantedAuthority> authorities = new ArrayList<GrantedAuthority>();
+    }
 
     /*
     /**********************************************************
@@ -30,7 +38,7 @@ static class PolyWrapper {
      */
 
     private final ObjectMapper MAPPER = objectMapper();
-    
+
     // // // Tests for [databind#1599]
 
     public void testXalanTypes1599() throws Exception
@@ -94,6 +102,17 @@ public void testC3P0Types1737() throws Exception
     }
     */
 
+        // // // Tests for [databind#1872]
+    public void testJDKTypes1872() throws Exception
+    {
+        ObjectMapper mapper = new ObjectMapper();
+        mapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
+
+        String json = aposToQuotes(String.format("{'@class':'%s','authorities':['java.util.ArrayList',[]]}",
+                Authentication1872.class.getName()));
+        Authentication1872 result = mapper.readValue(json, Authentication1872.class);
+        assertNotNull(result);
+    }
     private void _testIllegalType(Class<?> nasty) throws Exception {
         _testIllegalType(nasty.getName());
     }

src/test/java/org/springframework/jacksontest/GrantedAuthority.java

@@ -0,0 +1,5 @@
+package org.springframework.jacksontest;
+
+public interface GrantedAuthority {
+
+}