If an object is returned from the method, its reference might be assigned to a reference variable; : Garbage Collection « Java Source And Data Type « SCJP

1. SCJP
2. Java Source And Data Type
3. Garbage Collection

hence, it will not be eligible for collection. 

import java.util.Date;

public class MainClass {
   public static void main(String [] args) {
      Date d = getDate();
      System.out.println("d = " + d);
   }
   
   public static Date getDate() {
      Date d2 = new Date();
      StringBuffer now = new StringBuffer(d2.toString());
      System.out.println(now);
      return d2;
   }
}