Calculate Mathematical expression from a String input

class StringDemo27
{
static int expression(String s1)
{
int i, result;
String x[] = s1.split("\\+");
result = Integer.parseInt(x[0]);
for(i=1;i<x.length;i++)
{
result += Integer.parseInt(x[i]);
}
return result;
}
public static void main(String... s)
{
System.out.println(expression("10+20+20+20"));
}
}