#vulnerable code 
                                public void setPreferredRegion(String preferredRegion) {
        this.currentEndPoint = getObjectStoreCatalog().getRegion(preferredRegion);
    } 
                            #location 2 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public void setPreferredRegion(String preferredRegion) {
        this.preferredRegion = preferredRegion;
    }