http://vietjack.com/javaexamples/java_collections.jsp
Collection la mot frame work rat quan trong doi vs ngon ngu Java va duoc su dung mot cach rat thuong xuyen. 
Cung tim hieu them ve Collection qua hang loat cac vi du.
Moi nguoi co the dong gop y kien tren trang cua chung toi.
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