If the 

jsp:useBean

 element had a non empty body it is ignored. This completes the 

processing of this 

useBean

 action.

4.  If the object is not found in the specified scope and neither class nor beanName are given, 

a 

java.lang.InstantiationException

 shall occur. This completes the 

processing of this 

useBean

 action.

5.  If the object is not found in the specified scope; and the 

class

 specified names a non 

abstract class that defines a public no args constructor, then that class is instantiated, and 

the new object reference is associated the with the scripting variable and with the 

specified name in the specified scope using the appropriate scope dependent association 

mechanism (see 

PageContext

). After this, step 7 is performed.

If the object is not found, and the class is either abstract, an 

interface

, or no public 

no args constructor is defined therein, then a 

java.lang.InstantiationException

 shall occur. This completes the processing 

of this 

useBean

 action.

6.  If the object is not found in the specified scope; and 

beanName

 is given, then the method 

instantiate() of 

java.beans.Beans

 will be invoked with the ClassLoader of the 

Servlet object and the beanName as arguments. If the method succeeds, the new object 

reference is associated the with the scripting variable and with the specified name in the 

specified scope using the appropriate scope dependent association mechanism (see 

PageContext

). After this, step 7 is performed.

7. If the 

jsp:useBean

 element has a non empty body, the body is processed. The variable 

is initialized and available within the scope of the body. The text of the body is treated as 

elsewhere; if there is template text it will be passed through to the out stream; scriptlets 

and action tags will be evaluated.

A common use of a non empty body is to complete initializing the created instance; in 

that case the body will likely contain 

jsp:setProperty

 actions and scriptlets. This 

completes the processing of this 

useBean

 action.

Examples

In the following example, a Bean with name  connection  of type 

com.myco.myapp.Connection

  is available after this element; either because it was 

already created or because it is newly created.

In this next example, the 

timeout

 property is set to 33 if the Bean was instantiated.

Chapter 2

Standard Syntax and Semantics

62