title: Java: why Array.length has no () but String.length() does?
body: <p>Why when we get the length of an array don't we have to place ()
  like</p>
  
  <pre><code>int [] ar;
  System.out.println(ar.length); // no parentheses 
  </code></pre>
  
  <p>but for a String it will be</p>
  
  <pre><code>String st;
  System.out.println(st.length());
  </code></pre>