주민번호 유효성 체크

public static boolean isJumin( String jumin ) {
boolean isKorean = true;
int check = 0;
if( jumin == null || jumin.length() != 13 ) return false;
if( Character.getNumericValue( jumin.charAt( 6 ) ) > 4 && Character.getNumericValue( jumin.charAt( 6 ) ) < 9 ) {
isKorean = false;
}
for( int i = 0 ; i < 12 ; i++ ) {
if( isKorean ) check += ( ( i % 8 + 2 ) * Character.getNumericValue( jumin.charAt( i ) ) );
else check += ( ( 9 - i % 8 ) * Character.getNumericValue( jumin.charAt( i ) ) );
}
if( isKorean ) {
check = 11 - ( check % 11 );
check %= 10;
}else {
int remainder = check % 11;
if ( remainder == 0 ) check = 1;
else if ( remainder==10 ) check = 0;
else check = remainder;

int check2 = check + 2;
if ( check2 > 9 ) check = check2 - 10;
else check = check2;
}

if( check == Character.getNumericValue( jumin.charAt( 12 ) ) ) return true;
else return false;

}