variable « collection « Java Collection Q&A

1. if (variable == [any item in a collection]) in Java    stackoverflow.com

Let's say I have an array of primitives or a list of objects, doesn't matter, is there a short way of doing this kind of check:

if (a_primitive == any_item_in_my_collection) {
  ...

2. Returning new collection instead of existing collection instance variable    stackoverflow.com

I was having trouble understanding the following snippet:

public class Person {
   private List<Person> people = new ArrayList<Person>();

   public List<Person> getPeople() {
      return ...

3. Way to access variables of class from collection of its super?    stackoverflow.com

Suppose I have:

class Card{ }

class CardUnit extends Card {
  int attack = 4;
}

ArrayList<Card> listCards;

4. What java collection for large amount of data and user customizable variables?    stackoverflow.com

I'm trying to write an application which operates on large amount of data. I want user could customize data structure (record) from different types of variables(float,int,bool,string,enums). These records should be stored ...

5. Generic collection and instance variable    coderanch.com

Hi! When I compile and execute the following code: import java.util.*; public class ArrList { public static void main(String[] args) { List list = new ArrayList(); Base s1 = new Base(); Sub s2 = new Sub(); list.add(s1); list.add(s2); list.get(0).print(); System.out.println("s1(Base) s is \"" + list.get(0).s + "\""); System.out.println( "\n" ); list.get(1).print(); System.out.println("s2(Sub) s is \"" + list.get(1).s + "\""); System.out.println("s2(Sub) casted ...

6. Add long variable to a collection    forums.oracle.com

raychen wrote: Unfortunately bad things too Autoboxing is a double-edged sword. Can you list these bad things? Well performance for one. If you start thinking that List is just a flexible version of int[] then you could get in trouble. I think that actually happened recently. Someone was loading/processing an image of some sort using Lists of Integers. It's obviously not ...

7. Relationship with garabage collection and transient / volatile variables?    forums.oracle.com

Thanks jverd, Actually the question "Is there any relationship between garabage collection and transient / volatile variables?" was one of my interview question. I answered the same as you described but they were expecting something like in sense of whether transient / volatile variables are/not garbage collected ? If you have any idea,kindly share with me.Thanks. Sathiya

8. Collections' static variables    forums.oracle.com

Hi, In the utility class Collections there are three static variables: EMPTY_LIST EMPTY_MAP EMPTY_SET I used them often as a default value. This was good in pre 1.5. But with v1.5 you get a warning because these variables don't have a generic parameter type. So what is the suggested way, if you don't want to have any warnings? Don't use these ...