1. The Way aspect function calls are made are through proxy classes internally
2. Internally the Spring framework creates proxy classed and calls to the code generated as per the xml are run in proxy class methods before the actual class are called
3. In the below example in DrawingApp.java I try to create a object for the class circle by invoking factoryService getBean Method
4. This method returns a Object of class ShapeServiceProxy with the custom methods for xml code added

ShapeService.java

package com.mugil.shapes;

public class ShapeService {
	private Circle objCircle;
	private Triangle objTriangle;
		
	public Circle getObjCircle() {
		return objCircle;
	}
	public void setObjCircle(Circle objCircle) {
		this.objCircle = objCircle;
	}
	public Triangle getObjTriangle() {
		return objTriangle;
	}
	public void setObjTriangle(Triangle objTriangle) {
		this.objTriangle = objTriangle;
	}	
}

ShapeServiceProxy.java

package com.mugil.shapes;

public class ShapeServiceProxy extends ShapeService {
	
	public Circle getObjCircle() {
		new LoggingAspect().getLogMessage();
		return super.getObjCircle();
	}
}

DrawingApp.java

package com.mugil.shapes;

public class DrawingApp
 {
	public static void main(String[] args) 
        {
		FactoryService objFactSer = new FactoryService();
		ShapeService objSS = (ShapeService)objFactSer.getBean("ShapeService");
		objSS.getObjCircle();
	}
}

FactoryService.java

package com.mugil.shapes;

public class FactoryService {
	
	public Object getBean(String className)
	{
		if(className.equals("Circle"))
			return new Circle();
		else if(className.equals("Triangle"))
			return new Triangle();
		else if(className.equals("DrawingApp"))
			return new DrawingApp();
		else if(className.equals("ShapeService"))
			return new ShapeServiceProxy();
			
		return null;
	}
}