public class CompileTwice {
    public String message() {
        return "Hi again!";
    }
}
@@ -1,12 +1,66 @@
+import java.util.Collections;%0Aimport java.util.List;%0A%0A
 public class
@@ -90,14 +90,20 @@
 lic 
+List%3C
 String
+%3E
  mes
@@ -126,16 +126,42 @@
  return 
+Collections.singletonList(
 %22Hi agai
@@ -163,16 +163,17 @@
  again!%22
+)
 ;%0A    %7D%0A

Verify imports work when compiling incrementally