allow to override ProjectSettingsStepBase.findSequentNonExistingUntitled

platform/lang-impl/src/com/intellij/ide/util/projectWizard/ProjectSettingsStepBase.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -299,7 +299,8 @@ public class ProjectSettingsStepBase extends AbstractActionWithPanel implements
     return LabeledComponent.create(myLocationField, BundleBase.replaceMnemonicAmpersand("&Location"), BorderLayout.WEST);
   }
 
-  private static File findSequentNonExistingUntitled() {
+  @NotNull
+  protected File findSequentNonExistingUntitled() {
     return FileUtil.findSequentNonexistentFile(new File(ProjectUtil.getBaseDir()), "untitled", "");
   }
 }

platform/util/src/com/intellij/openapi/util/io/FileUtil.java

@@ -625,6 +625,7 @@ public class FileUtil extends FileUtilRt {
     return findSequentNonexistentFile(aParentFolder, aFilePrefix, aExtension).getName();
   }
 
+  @NotNull
   public static File findSequentNonexistentFile(@NotNull File parentFolder, @NotNull  String filePrefix, @NotNull String extension) {
     int postfix = 0;
     String ext = extension.isEmpty() ? "" : '.' + extension;