The document discusses Java components in Mule, including how to configure Java components using different implementations like DefaultJavaComponent and PooledJavaComponent. It also describes how to configure object factories, interceptors, entry point resolvers, and lifecycle interfaces for Java components.

2.  The Java component enables the developer to package custom Java code
that executes when the component receives a message
 Mule provides two JavaComponent implementations:
 DefaultJavaComponent, which configured with the `component `element
<component class="org.my.CustomComponent"/>
 PooledJavaComponent, which adds pooling functionality when configured
with the pooled-component element.
<pooled-component class="org.my.CustomComponent"/>
 To configure the Java component, selecting a class is the only required
entry.
 The class name can be specified either through the “Class Name”
attribute or the “Object” attribute.
 Using the “Class Name” attribute is equivalent to using the prototype
object factory
J a v a C o m p o n e n t s i n M u l e .

3.  Object factories manage both object creation in case of Mule instantiated
instance or object look up from another container such as Spring.
 The following object factories are included with Mule and can be configured
using Mule’s core schema.
Type 1:<prototype-object class=…"/> :Creates a new instance of the object on
each call.
Example: <component class="org.my.CustomComponent"/>
or
<component ><prototype-object class="org.my.CustomComponent">
</component>
Type2:<singleton-object class=…"/> :Creates an instance of the object once and
then always returns the same instance .
Example:<component>
<singleton-object class="org.my.CustomComponent"/>
</component>

4. Type 3: <spring-object bean=…"/> :This is an implementation of the ObjectFactory
interface which simply delegates to the Spring ApplicationContext. Since the
delegation happens each time a call to getOrCreate() is made, this will correctly
handle Spring beans which are non-singletons (factory beans, etc.)
Example:
<component>
<spring-object bean="myCustomComponentBean"/>
</component>
Interceptors:
 Interceptors let us provide additional services to the component
Example: the ability to log transactions and the ability to log the time for each
transaction.
 An interceptor contains the business logic that is applied to the message payload
before being sent to the next building block.
 The following types of interceptors can be added to the Java component:
a)Custom Interceptor
b)Logging Interceptor
c)Timer Interceptor

5. Entry Point Resolvers:
 The entry point is the method in our component that is invoked by Mule
when a message is received.
 Entry point resolver determine how our component is invoked when a
message is received by the flow
 helps us to determine which method of a Java component will be called.
 Each entry point resolver is tried in turn until one succeeds in delivering the
message to the component.
Reflection Entry point resolver:
 Determines the message to be invoked based on number and type of
arguments.
<component class=”org.my.PrototypeObjectWithMyLifecycle”>
<reflection-entry-point-resolver/>
</component>

6. Entry Point Resolvers:
Property Entry point resolver:
 Uses a mule message property to select the component method to be called.
<component class=”org.my.PrototypeObjectWithMyLifecycle”>
<property-entry-point-resolver property="propertyName"/>
</component>
The property-entry-point-resolver lets you choose a method to invoke at run-
time by adding this property name to the MuleMessage.
Method entry point resolver:
 Delivers the message to a named method.
<component class=”org.my.PrototypeObjectWithMyLifecycle”>
<method-entry-point-resolver>
<include-entry-point method="methodString" />
</method-entry-point-resolver>
</component>

7. Entry Point Resolvers:
Custom Entry point resolver:
 Allows user-supplied code to determine how a message is passed to a
component in Java. .
<component class=”org.my.PrototypeObjectWithMyLifecycle”>
<custom-entry-point-resolver
class="org.mule.test.integration.resolvers.CustomEntryPointResolver"
/>
</component>
Callable Entry point resolver:
 An entry point resolver for the components that implement the Callable
interface.
 This passes a MuleEventContext to the component.
 This entry point resolver is implicitly configured only if the component
implements the Callable interface.
<component class="org.my.PrototypeObjectWithMyLifecycle">
<callable-entry-point-resolver/>
</component>

8. Entry Point Resolvers:
Array Entry point resolver:
 Delivers the message to a method that takes a single array as
argument.
<component class=”org.my.PrototypeObjectWithMyLifecycle”>
<array-entry-point-resolver/>
</component>
No Arguments Entry point resolver:
 Calls a method without any arguments.
<component class=”org.my.PrototypeObjectWithMyLifecycle”>
<no-arguments-entry-point-resolver/>
</component>
Include Entry point:
 Includes a particular method to be invoked.
Can be used in combination with any other entry point resolver when
there is ambiguity

9. Component Life-Cycle Interfaces
A custom LifecycleAdaptor can be configured to customize
the way in which the component implementation is initialized
and disposed