String[] myArray = {"1", "2"};

String[] myArray = {"A", "B", "C"};

#ifdef ABC
  // ABC stuff here
#else
  // 123 stuff here
#endif

class Foo {

   static final boolean ABC = true;

   public void someMehod() {
       if (ABC) {  // #ifdef ABC

       } else {    // #else

       }           // #endif
   }
}

String[] myArray;
if (something)
    myArray = new String[]{"A", "B"};
else
    myArray = new String[]{"A", "B, "C"}

String[] myArray;

if (ABC)
myArray = ...
else
myArray = ...