Comments on: Mutable entries in a Collection http://javablog.co.uk/2008/10/19/mutable-entries-in-a-collection/ by Java coders, for Java coders Tue, 15 Nov 2011 21:34:57 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Javablog » Reading and Validating XML in Java with XPath http://javablog.co.uk/2008/10/19/mutable-entries-in-a-collection/comment-page-1/#comment-20779 Javablog » Reading and Validating XML in Java with XPath Sat, 15 Nov 2008 00:17:56 +0000 http://javablog.co.uk/?p=88#comment-20779 <p>[...] Javablog by Java coders, for Java coders « Mutable entries in a Collection [...]</p> […] Javablog by Java coders, for Java coders « Mutable entries in a Collection […]

]]> By: Michael http://javablog.co.uk/2008/10/19/mutable-entries-in-a-collection/comment-page-1/#comment-15852 Michael Sat, 01 Nov 2008 17:20:01 +0000 http://javablog.co.uk/?p=88#comment-15852 <p>Actually it's not threads that cause problems in these situations. </p> <pre><code> List<String> list = new ArrayList<String>(); Map<List<String>,String> map = new HashMap<List<String>,String>(); list.add("one"); map.put(list, "value"); list.add("two"); </code></pre> <p>This is problematic by itself in a single-threaded environment. Now if you publish state, i.e. if you were to expose the list variable, then threads can bring additional havoc.</p> Actually it’s not threads that cause problems in these situations. 


List<String> list = new ArrayList<String>();
Map<List<String>,String> map = new HashMap<List<String>,String>();
list.add("one");
map.put(list, "value");
list.add("two");

This is problematic by itself in a single-threaded environment. Now if you publish state, i.e. if you were to expose the list variable, then threads can bring additional havoc.

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