find first non-repeating char in string - JAVA language

public class Main {
	public static void main(String[] args) {

		String inputString = "test input string for first non repeating char z";
		String uniqueCharInInputStringString;

		int len = inputString.length();

		char testChar;
		boolean foundDuplicate;

		for ( int i = 0 ; i < len; i++ ){

			char testChar = inputString.charAt(i);

			foundDuplicate = false;

			for ( j = 0; j < len - i ; j++ ){

				if ( testChar == inputString.charAt(j) ) {

					foundDuplicate = true;
					break;

				}

			}

			if ( !foundDuplicate ) {

				uniqueCharInInputStringString = Character.toString(testChar);
				break;
			}


		}

		System.out.println( uniqueCharInInputStringString );

	}
}