new→ empty project→.......→.new→module→......→file→project structure →project→配置好project sdk→project language leval→選擇8開頭的（因為我們jdk是8）→apply→ok src→new ...
new→ empty project→.......→.new→module→......→file→project structure →project→配置好project sdk→project language leval→選擇8開頭的（因為我們jdk是8）→apply→ok
src→new→java class
