Question: I want to form a new string from ArrayList of Strings with a particular delimiter using spel.

```
list = ["a", "b", "c"]

```

I want to make a String s = "a,b,c" from above list.

I tried many expressions such as `StringUtils.join(list, ',')`, `list.stream().collect(Collectors.joining(','))`, etc.
but every time I'm getting an error

```
EL1008E: Property or field 'StringUtils' cannot be found on object of type 'java.util.LinkedHashMap' - maybe not public or not valid?

```

Is there any way to do this in spel?

Answer: 
If `StringUtils.join` is a static method, you need `T(com.my.StringUtils).join(...)` (need full class name too).
You can use this instead

```
String lst[] = new String[]{"a","b","c"};
System.out.println(String.join(",",lst)); //here output will be a,b,c

```