Using streams to convert a list of objects into a string obtained from the toString method

You can use the map and collect methods of the Stream class to achieve this. Here is an example:

List<Object> list = ...
String result = list.stream().map(Object::toString).collect(Collectors.joining(", "));

This will create a stream of the list, apply the toString method to each element of the stream, and then collect the resulting stream of strings into a single string, separated by commas.

Alternatively, you can use the reduce method to achieve the same result:

String result = list.stream().map(Object::toString).reduce((s1, s2) -> s1 + ", " + s2).orElse("");

This will concatenate the strings in the stream, starting with an empty string and using a comma as the separator. The orElse method is used to return an empty string if the stream is empty.