Java NullPointerException in if statement -

i nullpointerexception in following code.

else if (isempty(href))     system.err.println("this empty link: " + href); 

where isempty function following.

public boolean isempty(string href){     if (href.equals("") || href.equals("null") || href == null || href.isempty())           return true;     else          return false; } 

is because can not compare string null? can make function work?

your isempty test doing things in wrong order. change this:

if (href.equals("") || href.equals("null") || href == null || href.isempty())       return true; 

to:

if (href == null || href.equals("") || href.equals("null") || href.isempty())       return true; 

if href null, first test short-circuit rest of if , won't npe.

(by way, explicitly testing href.equals("") , calling href.isempty() redundant. need 1 or other.)

by by-the-way, recommend, matter of style simplifying method single return statement:

public boolean isempty(string href){     return href == null || href.isempty()) || href.equals("null"); } 

(also, if testing against string "null" attempt check against null value, can drop condition well. in fact, use apache commons' stringutils.isempty(charsequence) method want.)