??菜单window->Preferences->Java->Editor->Content Assist->Enable auto activation 选项要打上勾。
还有windows-->preference-->workbench-->keys 下设置Content??? Assist??? 的快捷键。不能自动提示。
??需要设置：window->Preferences->Java->Editor->Content Assist->Advanced?? 上面的选项卡Select the proposal kinds contained in the 'default' content assist list: 中把 Other Java Proposals 选项打上勾就可以了