How to check two strings or sentences are Anagram using StringBuilder class

import java.util.Scanner;

class CheckAnagramByDeletingChars {

	public static void main(String[] args) {

		Scanner inpStr=new Scanner(System.in);
		System.out.println("Enter first line");
		String secondLine=inpStr.nextLine();

		//Converting the input line to lower case by excluding spaces and store into firstLine stringBuilder variable
		StringBuilder firstLine=new StringBuilder(secondLine.replaceAll("\\s", "").toLowerCase());
		System.out.println("Enter second line");
		secondLine=inpStr.nextLine();

		//Converting the second input line to lower case by excluding spaces
		secondLine=secondLine.replaceAll("\\s", "").toLowerCase();
		inpStr.close();	
		Boolean isAnagram=true;

		//Check the availability of each character from the firstLine (StringBuilder) in the secondLine, if available delete the same from firstLine
		while (firstLine.length()>0) {
			if (secondLine.contains(String.valueOf(firstLine.charAt(0)))==true)
				firstLine.deleteCharAt(0);
			else {
				isAnagram=false;
				break;
			}
		}
		//If all characters of firstLine available in second line, Anagram always have default value true
		if (isAnagram==true)
			System.out.println("Both input lines are Anagram");
		else
			System.out.println("Both input lines are not Anagram");
	}
}