1. Interface supports multiple inheritance

class Class_A { }
class Class_B { }
abstract class MyAbstractClass extends Class_A, Class_B { }

Parse error:  syntax error, unexpected ',', expecting '{' in...

. 2. Interface contains only incomplete member (contains only signature of a method)

interface Animal {
    function run() {
        echo 'I am running!';
    }
}

Fatal error:  Interface function Animal::run() cannot contain body in ...

. 3. Interface does not contain data member

interface MyInterface {
    public $foo = null;
}

Fatal error:  Interfaces may not include member variables in ...

. 4. Interface can not have access modifiers (other than

public

), by default everything is assumed as public

interface iTemplate
{
    private function setVariable($name, $var);
    public function getHtml($template);
}

Fatal error:  Access type for interface method iTemplate::setVariable() must be omitted in ...

. Notes (mistakes on the page): 1. Interface does contain CONSTRUCTOR (but can force child classes to implement constructor) as well as abstract class can contain one

interface MyInterface {
    function __construct();
}
class mathh implements MyInterface {
    // function __construct(){ }
}

2. We can have static methods inside interface as well as inside abstract classes

interface MyInterface {
    static function getPI();
}
class mathh implements MyInterface {
    static function getPI(){
        return 3.1415926535;
    }
}

3. Abstract class can contain abstract static member

abstract class Animal {
    // child classes must implement this
    abstract static function prey();

    static public function run() {
        echo "I am running!\n";
    }
}
class Dog extends Animal {
    static public function prey() {
        echo "I killed the cat !\n";
    }
}
$dog = new Dog();
$dog->prey(); // I killed the cat !