Static Members in PHP OOPS

<?php

//  Example 1
class Abc {
    public static $data = "test data";
    public static $size = "big data here";
    public static function xyz() {
        echo "xyz function <br>";
    }

    public static function getSize() {
        return self::$size;
    }

    public static function setSize($s) {
        return self::$size = $s;
    }
}
echo Abc::$data . "<br>";
Abc::xyz() . "<br>";
echo Abc::getSize() . "<br>";
echo Abc::setSize(1200) . "<br><br><br>";

//  Example 2
class AbcTwo {
    public static $objectCount = 0;
   
    public static function getCount() {
        return "Total Objects created by class are : " . self::$objectCount;
        echo "Hello this is getCount function called <br>";
    }
   
    public function __construct() {
        self::$objectCount++;
    }
}
$a = new AbcTwo();
$b = new AbcTwo();
$c = new AbcTwo();
$d = new AbcTwo();
$e = new AbcTwo();

echo AbcTwo::getCount();

// OUTPUT :
//test data
// xyz function
// big data here
// 1200


// Total Objects created by class are : 5

?> 

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