Why is it necessary to precede the variable with the type of the variable?

Question

Java

Please explain to the php-shnik why when declaring a function, it is necessary to put the name of the class before the variable name? For example Circle var;
And why in a method before parameters it is necessary to interpose type?
public function (String a) {
}
whereas in php you can just
public function (a) {
}

Answer 1

Static typing