or statement optimisation in android -

i have 2 list: list1,list2. traversal 2 list , combine them 1 list. use such statement:

if(list1 != null && list2 != null) {   int i=0,j=0;       while(i<list1.size() || j<list2.size())    {  if((j>=list2.size()) || (curformater.parse(list1.get(i).recorddate).compareto(curformater.parse(list2.get(j).recorddate)) < 0))                {     .....                    i++;            }     else if((i>=list1.size()) || (curformater.parse(list1.get(i).recorddate).compareto(curformater.parse(list2.get(j).recorddate)) < 0))     {     .....   j++;  }   ....      } 

in these 2 if-statements, when j>=list2.size() or i>=list1.size(), latter condition should not judged,but java compiler seems judge them , throw indexoutofboundsexception. how can let java not excute latter condition judgement? in advance!

when want merge 2 lists have different size, index smallest list finish iterate earlier largest list, have use && operator.

if(list1 != null && list2 != null) {    int i=0,j=0;        while(i<list1.size() && j<list2.size())      {       // code       i++;        j++;   }   // when 1 of them arrived end of list loop not executed need check   // conditions  while (i > list.size() && j < list.size())  {        // code        j++;  }  while (i < list.size() && j > list.size())  {        // code       i++;  } 

so optimization, time complexity o(m+n) if assume there m elements in list1 , n elements in list2, 2 while loops executed

edit

or , and operators binary operators, means must check 2 conditions combine, while not unary alwyas need 1 condition check..
if heard truth tables of operators, compilers programmed work based on truth tables, when see || (or operator) checks conditions truth table of or, when see && (and operator) checks conditions truth table of and. , since both or , and binary operators both of condition 'juded' 1 of them true.

or truth table

(assume , b statemnts (conditions) , r result when or on them

-------------------------      |   b   |  r  -------------------------    true | true  |  true   -------------------------   true | false |  true   -------------------------   false| true  |  true -------------------------    false| false |  false -------------------------    // in or table, when both of conditions false result false  // while when 1 of them true result true 

and truth table

(assume , b statemnts (conditions) , r result when , on them

-------------------------      |   b   |  r  -------------------------    true | true  |  true   -------------------------   true | false |  false   -------------------------   false| true  |  false -------------------------    false| false |  false -------------------------   // in , table, when both of conditions true result true // while when 1 of them false result false 

i hope understand why 2 conditions must checked if 1 of them true.. example, lets have 2 conditions , b , or on them , assume false

if (a || b) // code here 

in case depends in condition b, if b false code not executed, if b true code executed..

i know asked why if true still checking b condition, it's because or binary operator..