how to convert from Arraylist to string[] in java code example

Example 1: java arraylist to string

ArrayList<String> al = new ArrayList<String>();
      al.add("Hello");
      al.add("Wor");
      al.add("ld");
      StringBuffer sb = new StringBuffer();
      
      for (String s : al) {
         sb.append(s);
         sb.append(" ");
      }
      String str = sb.toString();
      System.out.println(str);//"Hello wor ld"

Example 2: arraylist string to string array

String[] arr = list.toArray(new String[list.size()]);

Example 3: java string array to arraylist

new ArrayList( Arrays.asList( new String[]{"abc", "def"} ) );