2、window->preferences->java->Compiler->设置右侧的Compiler compliance level
3、window->preferences->java->Installed JREs->设置或者选择右侧的Installed JREs
2、window->preferences->java->Compiler->设置右侧的Compiler compliance level
3、window->preferences->java->Installed JREs->设置或者选择右侧的Installed JREs