しかたがないにゃ〜

Scratch.java

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

class Scratch {

  public static void main(final String[] args) {
    final InputStream inputStream = new ByteArrayInputStream("foo,\nbar,\n,baz".getBytes(StandardCharsets.UTF_8));
    final String string = toString(inputStream);
    System.out.println(string);
  }

  private static String toString(final InputStream inputStream) {
    try(inputStream) {
      final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
      inputStream.transferTo(outputStream);
      return outputStream.toString(StandardCharsets.UTF_8);
    }
  }
}