A random integer between (int)'a' and (int)'z' is, (int)((int)'a' + Math.random() * ((int)'z' - (int)'a' + 1). every character has a unique Unicode between 0 and FFFF in hexadecimal (65535 in decimal). To generate a random character is to generate a random integer between 0 and 65535 using the following expression (note that since 0 <= Math.rand…

RandomCharacter.java

package learnjava.general;

/**
 * Created by Isuru on 23/03/2017.
 */
public class RandomCharacter {

    /** Generates random character */
    public static char getRandomCharacter(char ch1, char ch2){
        return (char) (ch1 + Math.random() * (ch2 - ch1 + 1));
    }

    /** Generate a random lowercase letter */
    public static char getRandomLowerCaseLetter(){
        return getRandomCharacter('a', 'z');
    }

    /** Generate a random uppercase letter */
    public static char getRandomUpperCaseLetter(){
        return getRandomCharacter('A', 'Z');
    }

    /** Generate a random digit character */
    public static char getRandomDigitalCharacter(){
        return getRandomCharacter('0', '9');
    }

    public static char getRandomCharacter(){
        return getRandomCharacter('\u0000', '\uFFFF');
    }

    public static void main(String args[]){
        final int NUMBER_OF_CHARS = 175;
        final int CHARS_PER_LINE = 25;

        // Print random characters between 'a' and 'z', 25 chars per line
        for(int i = 0; i < NUMBER_OF_CHARS; i++){
            char ch = RandomCharacter.getRandomLowerCaseLetter();
            if((i + 1) % CHARS_PER_LINE == 0){
                System.out.println(ch);
            }else{
                System.out.print(ch);
            }
        }
    }
}