if(args.length == wantedAmount) {
    // DO CODE
} else if(args.length == anotherWantedAmount) {// Only if command takes different amount of arguments, add as many else ifs as needed
    // DO CODE
} else {
    // Invalid Arguments
}

// DON'T DO THIS!!!!!!!!!!!
if(args.length == 0)
// You don't always have to use ==
// You can also use > or < or >= or <=
// DON'T WASTE YOUR TIME!