package com.company;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main
{
    private String str(){
        String  str="00!!!0* dsgsh235 !!!=-lktrfgho";
        Pattern r = Pattern.compile("[-[0-9]_!@#$%&*()+=\s+]");
        Matcher b = r.matcher(str);

        Pattern pat = Pattern.compile("[A-Z+][a-z+]");
        Matcher mat = pat.matcher(str);
        return str;

    }
    public static void main(String[] args)
    {
        String str="00!!!0*dAsgsh235 !!!=-lktKHrfgho";
        Pattern pat = Pattern.compile("[^(A-Za-z)]+");
        Matcher mat = pat.matcher(str);
        while (mat.find()) System.out.print(mat.group());

    }

}

Pattern pattern = Pattern.compile("[^a-zA-Z]+");
    Matcher matcher = pattern.matcher("asd2$%*^$^#22l######khlh4444lklkb!!!!!!!");
    int maxLenght = 0;
    while (matcher.find()){
        int lenght = matcher.group().length();
        // System.out.println(matcher.group()); // debug
        if (lenght > maxLenght) maxLenght = lenght;
    }
    System.out.println(maxLenght);