string remove last character

private static String removeLastChar(String str) {
    return str.substring(0, str.length() - 1);
}

public static String removeLastCharacter(String str) {   
	String result = null;   
    if ((str != null) && (str.length() > 0)) {      
    	result = str.substring(0, str.length() - 1);   
    }   
    
    return result;
}

let str = "Hello world"
let strWithoutLastChar = str.substring(0, str.length - 1)

public String method(String str) {
    if (str.charAt(str.length()-1)=='x'){
        str = str.replace(str.substring(str.length()-1), "");
        return str;
    } else{
        return str;
    }
}