Implement methods of an interface or abstract class

If a class is declared as implementing a certain interface or extending a class with abstract methods, it has to implement the methods of such interface or class. IntelliJ IDEA creates stubs for implemented methods, with the default return values for the primitive types, and null values for the objects.

Implement required methods

From the main menu, select Code | Implement methods or press Ctrl+I. You can also right-click anywhere in the class file, then click Generate Alt+Insert, and select Implement methods.
In the dialog that opens, select the methods to implement. If necessary, select the Copy JavaDoc checkbox to insert JavaDoc comments for the implemented methods.
Click OK.

Change method body

The code template used for implementing methods (Implemented method body) accepts predefined template variables from the File Header include template (such as ${USER}, ${DATE}, and so on)

For example, consider the following file template:

            #if ( $RETURN_TYPE != "void" )return $DEFAULT_RETURN_VALUE;#end
            // TODO ($USER, $DATE):To change the body of an implemented method, use File | Settings - Editor -  File and Code Templates.
        

Provided that the implemented interface contains two methods, this template expands into the following code:

            @Override
            public void hunt() {
                // TODO (wombat, 9/21/12): To change the body of an implemented method, use File | Settings - Editor -  File and Code Templates.
            }
            @Override
            public String sniff() {
                return null;  // TODO (wombat, 9/21/12): To change body of implemented methods use File | Settings - Editor - File and Code Templates.
            }
        

Last modified: 08 March 2021