title: Why writeBufferSize in abstract class Writer be declared as final?
body: <pre><code>public abstract class Writer implements Appendable, Closeable, Flushable {
      /**
       * Temporary buffer used to hold writes of strings and single characters
       */
      private char[] writeBuffer;
      /**
       * Size of writeBuffer, must be &gt;= 1
       */
      private final int writeBufferSize = 1024;
  </code></pre>
  
  <p>I just want to set the writeBufferSize to a bigger number。Why the designer declared it as final? </p>