AnExample.java

public class AnExample {
  public static void main(String[] args) {
    System.out.println(
      ColoredString.s("Such ANSI, Easy Color. Many wow.").bold().cyan().blink();
    );
  }
}

ColoredString.java

package com.reliablerabbit.colors;

public class ColoredString {
        private String s;
        private int options;
        public ColoredString(String s)          { this.s = s; }
        public ColoredString(ColoredString c)   { this.s = c.getS(); }
        public static ColoredString s(String s) { return new ColoredString(s); }
        public String getS()                    { return s; }

        // font modifiers
        public ColoredString bold()      { options = options | Colors.BOLD;      return this; }
        public ColoredString underline() { options = options | Colors.UNDERLINE; return this; }
        public ColoredString blink()     { options = options | Colors.BLINK;     return this; }

        // text colors
        public ColoredString black()   { options = options | Colors.BLACK;   return this; }
        public ColoredString red()     { options = options | Colors.RED;     return this; }
        public ColoredString green()   { options = options | Colors.GREEN;   return this; }
        public ColoredString yellow()  { options = options | Colors.YELLOW;  return this; }
        public ColoredString blue()    { options = options | Colors.BLUE;    return this; }
        public ColoredString magenta() { options = options | Colors.MAGENTA; return this; }
        public ColoredString cyan()    { options = options | Colors.CYAN;    return this; }
        public ColoredString white()   { options = options | Colors.WHITE;   return this; }

        // render
        @Override
        public String toString() {
                // if netbeans: return Colors.c( options & Colors.COLOR_MASK, s );
                // if windows: return s;
                // if NIX: return Colors.c(options, s);
                return Colors.c(options, s);
        }

        public String rainbow() {
                StringBuffer rainbow = new StringBuffer();
                char[] characters = s.toCharArray();
                short[] colors    = { Colors.RED, Colors.YELLOW, Colors.GREEN, Colors.CYAN, Colors.BLUE };
                int offset        = (int) (System.nanoTime() % colors.length);

                for(int i = 0; i < characters.length; i++) {
                        short color = colors[ ((i + offset) % colors.length) ];
                        rainbow.append( Colors.c(options | color, String.valueOf(characters[i])) );
                }

                return rainbow.toString();
        }
}

Colors.java

package com.reliablerabbit.colors;

public class Colors {
        public final static short BLINK     = 4096;
    public final static short BOLD      =    1;
    public final static short UNDERLINE =    4;

    public final static short BLACK      =   16;
    public final static short RED        =   32;
    public final static short GREEN      =   64;
    public final static short YELLOW     =  128;
    public final static short BLUE       =  256;
    public final static short MAGENTA    =  512;
    public final static short CYAN       = 1024;
    public final static short WHITE      = 2048;
    public final static short COLOR_MASK = 0x3fb;

    public final static String CLEAR_SCREEN = "\033[2J\033[;H";

    public static String c(int options, String s) {
        StringBuffer buff = new StringBuffer();

        if((options & Colors.BOLD)      == Colors.BOLD)      buff.append("\u001B[1m");
        if((options & Colors.UNDERLINE) == Colors.UNDERLINE) buff.append("\u001B[4m");
        if((options & Colors.BLINK)     == Colors.BLINK)     buff.append("\u001B[5m");

        if((options & Colors.BLACK)     == Colors.BLACK)     buff.append("\u001B[30m");
        if((options & Colors.RED)       == Colors.RED)       buff.append("\u001B[31m");
        if((options & Colors.GREEN)     == Colors.GREEN)     buff.append("\u001B[32m");
        if((options & Colors.YELLOW)    == Colors.YELLOW)    buff.append("\u001B[33m");
        if((options & Colors.BLUE)      == Colors.BLUE)      buff.append("\u001B[34m");
        if((options & Colors.MAGENTA)   == Colors.MAGENTA)   buff.append("\u001B[35m");
        if((options & Colors.CYAN)      == Colors.CYAN)      buff.append("\u001B[36m");
        if((options & Colors.WHITE)     == Colors.WHITE)     buff.append("\u001B[37m");

        buff.append(s);
        buff.append("\u001B[0m");
        return buff.toString();
    }
}