In my android studio project want to use existing java project code
I tried this way:
Click File > New Module. Select Java Library and click Next.>
It is not possible to access with out gradle file,
you can use these steps if your Java project in eclipse
1.Right Click on project select export a new window appears
2.Select generate gradle build file then the select project click finish
It will create your project with gradle file,then you can easily import
File -> New -> Import module.....