@CheckForNull

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

@@ -371,7 +371,7 @@ public abstract class Node extends AbstractModelObject implements Reconfigurable
      *      null if this node is not connected hence the path is not available
      */
     // TODO: should this be modified now that getWorkspace is moved from AbstractProject to AbstractBuild?
-    public abstract FilePath getWorkspaceFor(TopLevelItem item);
+    public abstract @CheckForNull FilePath getWorkspaceFor(TopLevelItem item);
 
     /**
      * Gets the root directory of this node.
@@ -384,7 +384,7 @@ public abstract class Node extends AbstractModelObject implements Reconfigurable
      *      null if the node is offline and hence the {@link FilePath}
      *      object is not available.
      */
-    public abstract FilePath getRootPath();
+    public abstract @CheckForNull FilePath getRootPath();
 
     /**
      * Gets the {@link FilePath} on this node.

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

@@ -57,6 +57,7 @@ import java.util.Set;
 import javax.servlet.ServletException;
 
 import hudson.util.TimeUnit2;
+import javax.annotation.CheckForNull;
 import jenkins.model.Jenkins;
 import jenkins.slaves.WorkspaceLocator;
 
@@ -284,7 +285,7 @@ public abstract class Slave extends Node implements Serializable {
      * @return
      *      null if not connected.
      */
-    public FilePath getWorkspaceRoot() {
+    public @CheckForNull FilePath getWorkspaceRoot() {
         FilePath r = getRootPath();
         if(r==null) return null;
         return r.child(WORKSPACE_ROOT);