package object_out; import java.util.HashMap; import java.util.concurrent.ConcurrentHashMap; public class TestReplaceFormWithBooleanReturn { ConcurrentHashMap hm = new ConcurrentHashMap(); public void doReplace() { hm.replace("a_key", "old_value", "new_value"); } public void doReplace2() { hm.replace("a_key", "old_value", "new_value"); } }