java - How to output variables from nested for loops using BigIntegers -

i getting mad errors when try implement program wrote solve leonhard euler's conjecture. error seems in println. know i'm doing wrong? (there no errors before run program, error messages appear after) i'm implementing simple i'm not quite sure why not cooperating.

p.s. read on website assign out message string object , print string object, adds error message list.

    public static void main(string[] args) {      biginteger max = new biginteger("integer.max_value");      // for(int a=0; a<max; a++)     for(biginteger a=biginteger.zero; a.compareto(max)<=0; a=a.add(biginteger.one)){          for(biginteger b=biginteger.zero; b.compareto(max)<=0; b=b.add(biginteger.one)){              for(biginteger c=biginteger.zero; c.compareto(max)<=0; c=c.add(biginteger.one)){                  for(biginteger d=biginteger.zero; d.compareto(max)<=0; d=d.add(biginteger.one)){                      // a^4                     a=a.pow(4);                     // b^4                     b=b.pow(4);                     // c^4                     c=c.pow(4);                     // d^4                     d=d.pow(4);                      // a+b+c                     biginteger sum = new biginteger("a.add(b).add(c)");                      // if( sum == d^4 )                     int euler = sum.compareto(d);                     if( euler ==0)                     {                         system.out.println(a+"^4+"+b+"^4+"+c+"^4="+d+"^4");                     }                   }             }         }     }    } 

two things can spot 'probably wrong'.

biginteger max = new biginteger("integer.max_value"); 

what want is:

biginteger max = biginteger.valueof((long)integer.max_value); 

and also:

biginteger sum = new biginteger("a.add(b).add(c)"); 

try instead:

biginteger sum = a.add(b).add(c)