public static long GCD ( long n1 , long n2 ) {
  if ( n1 == 0 ) {
    return n2 ;
  }
  return GCD ( n2 % n1 , n1 ) ;
}

public static long GCD ( long n1 , long n2 ) { if ( n1 == 0 ) { return n2 ; } return GCD ( n2 % n1 , n1 ) ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier)) (formal_parameter type: (integral_type) name: (identifier))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (return_statement (identifier)))) (return_statement (method_invocation name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)) (identifier))))))