This document discusses different ways to use Java components in Mule flows: 1. A "noArguments" method can be invoked by setting the payload to null before the Java component. 2. Annotated entry points allow specifying the entry point method based on annotations like @Payload and @OutboundHeaders. 3. A Java component can invoke an external HTTP service and return the response, allowing services to be called from Java code.

1. MULE JAVA CUSTOM COMPONENT - 4
Ravinder

2. No Arguments method:
 Drag a 'Set Payload' component and set value a string value as
"#[null]". So that payload becomes null. Drag a java component and
refer to a class "EntryPointResolver" as shown earlier.

3.  As payload is null after 'Set payload' component,
"noArgumentsMethod()" method of "EntryPointResolver" Class gets
invoked.
Annotated Entry Point Resolver:
 Annotated Entry Point Resolver is used to determine the entry
point of the component using annotations.
Example:
 In below flow 'Set Payload' component has been used to set a
String as "RAM" and 'Property' component has been to create
outbound property (dept = IT). A Java component is used to refer a
java class "AnnotatedEntryPointerResolver".

4.  Below java class has a method multipleArgumentsMethod(@Payload
String name, @OutboundHeaders Map<String, Object> dept) which
has two arguments referred by annotations. Based on the annotation
the respective value gets match to the argument.

5.  For example, payload value matches to the argument 'name'.
@Payload String name
 In the same way, all outbound properties match to the argument 'dept'
which is type java.util.Map.
@OutboundHeaders Map<String, Object> dept

6. Invoking a service using java component:
 In this example a java component is reffered to a class
"HTTPInvocation" which invokes another HTTP service and returns
the HTTP resoponse. Logger component is used to log the response.

7. Java Class:

9. Thank You All