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    <p>Java and PHP (even when using OO PHP) have a vast array of differences.</p> <p>Just a few thoughts off the top of my head:</p> <ol> <li><p>Java is strongly-typed, PHP is not, although there is a limited scope for type-hinting in PHP. This makes a huge difference to method signatures. In PHP, you can only force method parameters to be of a certain class or interface or an array:</p> <p><code>public function myMethod(SomeClass $foo, array $bar){}</code></p> <p>...but you cannot type-hint for primitives! So <code>public function myMethod(int $foo, boolean $bar){}</code> is invalid and will throw a parse error.</p> <p>Furthermore, any parameter that has been type-hinted cannot be passed as <code>null</code> <em>unless <code>null</code> is given as a default value</em>. So to allow <code>null</code>s, you need to use:</p> <p><code>public function myMethod(SomeClass $foo = null)</code></p></li> <li><p>PHP does not require (or even support) specifying the return type of a function.</p></li> <li><p>PHP classes do not have <code>final</code> fields, although what would be a <code>static final</code> field in Java is a <code>const</code> in PHP. EDIT: A <code>const</code> in PHP is more limited than a <code>static final</code> in Java as the latter can be an array or object instance, whereas the former must be a constant value (number or a string, essentially).</p></li> <li><p>"Overloading" in PHP does not mean the same as it does in Java. In Java, it means specifying multiple methods of the same name, but with a different set of parameters:</p> <p><code>public void myMethod(int foo){}; public void myMethod(float foo){};</code></p> <p>In PHP, it refers to the dynamic creation of properties and methods using the <code>__get()</code>, <code>__set()</code> and <code>__callStatic()</code> "magic" methods. See the <a href="http://uk3.php.net/manual/en/language.oop5.overloading.php" rel="noreferrer">PHP manual</a> for a description on their use. Java-style method overloading is impossible in PHP and an attempt to redeclare a method (with or without a different set of parameters) will fail.</p></li> <li><p>May be obvious to some, but in PHP you use <code>::</code> to access static methods and properties and <code>-&gt;</code> to access instance ones, but in Java <code>.</code> is used for both.</p></li> <li><p>PHP doesn't have packages, but it does have <em>namespaces</em>.</p></li> <li><p>As of PHP5, constructors in PHP are not supposed to be methods with a name that matches the class, like in Java, but the magic method <code>__construct()</code> should be declared instead, although the PHP4 style is supported for backward-compatibility. Also, PHP has a destructor method named <code>__destruct()</code>.</p></li> <li><p>In Java, all classes inherit from <code>Object</code>, but there is no such generic super-class in PHP.</p></li> <li><p>Even when maximizing the amount of OOP in a PHP script, it still relies on a procedural flow; there's no class-level entry point like in Java (i.e., <code>public static void main(String[] args)</code> or <code>public void init()</code> for applets).</p></li> </ol>
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    1. POSubtle oop differences between java and php
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    1. CO`const` and `final` are semantically different anyway.
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    2. COYes they are. My point is that the closest you can get to Java's `static final` in PHP is a `const` and that PHP has no property-level `final` equivalence.
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