Merge pull request #2766 from jglick/NPE-JENKINS-42367

Noting that ParameterValue.getValue can on occasion return null

core/src/main/java/hudson/model/ParameterValue.java

@@ -36,6 +36,7 @@ import java.io.IOException;
 import java.io.Serializable;
 import java.util.Map;
 import java.util.logging.Logger;
+import javax.annotation.CheckForNull;
 import jenkins.model.Jenkins;
 
 import net.sf.json.JSONObject;
@@ -302,9 +303,11 @@ public abstract class ParameterValue implements Serializable {
      * Returns the most natural Java object that represents the actual value, like
      * boolean, string, etc.
      *
-     * If there's nothing that really fits the bill, the callee can return {@code this}.
+     * @return if there is no natural value for this parameter type, {@code this} may be used;
+     *         {@code null} may be used when the value is normally defined but missing in this case for various reasons
      * @since 1.568
      */
+    @CheckForNull
     public Object getValue() {
         return null;
     }