openide/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/foldIntoStream/afterConcatCharDelimiter.java

// "Fold expression into 'String.join'" "true-preview"
class Test {
  String  foo(String a, String b, String c) {
    String s = String.join("_", a, b, c);
    return s;
  }
}