nctionMapper</code></a>, and
 <a href="VariableMapper.html" title="class in jakarta.el"><code>VariableMapper</code></a> are not stored for future use and do not have to be <code>Serializable</code>.

 <p>
 The <code>createValueExpression</code> and <code>createMethodExpression</code> methods must be thread-safe. That is,
 multiple threads may call these methods on the same <code>ExpressionFactory</code> object simultaneously.
 Implementations should synchronize access if they depend on transient state. Impl