Verify that Java is installed on your system. To do this, open a terminal and type the following command: Java -version. Mac OS X comes pre-installed with the Java runtime environment and its corresponding Java developer kit (JDK).

Open Xcode create a new project based on the empty template under the OS X tab. Users familiar with out-of-date versions of Xcode (the current version of Xcode as of October 2018 is Xcode 10.1) might remember that there used to be templates dedicated to different types of Java applications, but this is no longer the case. You will be presented with a completely bare Xcode project.

Create the Java main file for your application by selecting “New File” from the file menu and naming the file “Main” with the “.java” extension; all Java applications must have a main file.

Right-click on the left pane of the IDE and select the “Add Group” option. This will create a folder with a name of your own choosing within the project, allowing you to organize your Xcode project in a logical manner.

Begin writing the code for your application. Assuming there is nothing wrong with your Xcode installation or your Java installation, Xcode should automatically provide syntax for your Java code.