SdkReferenceItem (@NotNull SdkType type, @NotNull String name, @Nullable String versionString, boolean isValid) { SdkReferenceItem element = new SdkReferenceItem(type, name, versionString, isValid); //similar element might already be included! removeSdkReferenceItem(element); ImmutableList.Builder<SdkReferenceItem> builder = ImmutableList.builder(); builder.addAll(myReferenceItems); builder.add(element); myReferenceItems = builder.build(); syncModel(); return element; }