java - NullPointerException without referencing any object -

i have piece of code, throws nullpointerexception sometimes. far not interesting. exception occurs in line, not reference object.

    try     {       parser.parse(input);/*line 186*/      }     catch(exception e)     {       //npe happens in next line?       throw new saxexception("error parsing document", e);/*line 190*/     } 

here stacktrace

  java.lang.nullpointerexception     @ com.tejoe.myxmlparser.parse(myxmlparser.java:190)     @ com.tejoe.myxmlparser.parse(myxmlparser.java:168)     .... 

it happened twice in last 3 months , code run @ least hundred thousand times.

i decompiled code, make sure line information correct , yes are.

additional test

there seems special saxexception. did following test:

import org.xml.sax.saxexception;  public class test {   public static void main(string[] args) throws exception   {     new saxexception("error", new nullpointerexception()).printstacktrace();   } } 

i got following output

java.lang.nullpointerexception   @ test.main(test.java:7) caused by: java.lang.nullpointerexception   ... 1 more 

solution: saxexception overrides tostring method, return name of cause exception.

now wonder, did not caused output in production environment (aix java)

i wrote following code , generated null pointer exception. came on line 45 follow,

exception in thread "main" java.lang.nullpointerexception     @ inheritance.parent.child.main(child.java:45)  import org.xml.sax.saxexception;  public class child  {  public static void main(string[] args) throws saxexception {          try{         child c1 = null;         c1.i=0;          } catch(exception e){             throw new saxexception("error", e); //line : 45         }     } } 

the error code proper. need find object getting null.