added a test to check for regressions in JENKINS-15105.

core/src/test/java/jenkins/ResilientJsonObjectTest.java

+package jenkins;
+
+import net.sf.json.JSONObject;
+import org.junit.Test;
+import org.jvnet.hudson.test.Bug;
+
+/**
+ * @author Kohsuke Kawaguchi
+ */
+public class ResilientJsonObjectTest {
+    public static class Foo { int a; }
+
+    /**
+     * {@link JSONObject} databinding should be able to ignore non-existent fields.
+     */
+    @Test
+    @Bug(15105)
+    public void databindingShouldIgnoreUnrecognizedJsonProperty() {
+        JSONObject o = JSONObject.fromObject("{a:1,b:2}");
+        Foo f = (Foo)JSONObject.toBean(o,Foo.class);
+        assert f.a == 1;
+    }
+}