java - Thread-Safety in a class -


please can have @ following code , advise whether classa thread-safe or not? if not thread-safe, please advise breaking?

public class classa {  private list<player> players;  public classa() { this.players = collections.synchronizedlist(new arraylist<player>()); }  public player play(player player){ int score = 0; . . .  if (players.contains(player)) { player = players.get(players.indexof(player)); player.addscore(score); } else { player.addscore(score); players.add(player); } return player;  }  }

no, not.

for example, 2 threads fail players.contains test , both add version of player (a better way add player every time set). also, unless player.addscore thread-safe, score adding subtly wrong.

synchronizing on whole play method (and reverting of players normal list) solve these problems.


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