Reproducible code:

<?php

class A {

    const CONSTANT = "CONSTANT";

    public static $staticField = "static field";

    public static function staticMethod() {
        return "staticMethod()";
    }

}

$a = new A();
echo $a::CONSTANT . PHP_EOL; // doesn't work on CONSTANT
echo $a::$staticField . PHP_EOL; // doesn't work on $staticField
echo $a::staticMethod() . PHP_EOL; // doesn't work on staticMethod

A::CONSTANT; // works fine
A::$staticField; // works fine
A::staticMethod(); // works fine

my environment:
Product Version: NetBeans IDE 8.1 (Build 201510222201)
Java: 1.8.0_74; Java HotSpot(TM) 64-Bit Server VM 25.74-b02
Runtime: Java(TM) SE Runtime Environment 1.8.0_74-b02
System: Linux version 3.13.0-83-generic running on amd64;

Thanks.