jodd-servlet/src/main/java/jodd/servlet/ServletUtil.java
public static boolean isAbsoluteUrl(final String url) {
	    if (url == null) {      	    // a null URL is not absolute
		    return false;
	    }
	    int colonPos;                   // fast simple check first
	    if ((colonPos = url.indexOf(':')) == -1) {
		    return false;
	    }

	    // if we DO have a colon, make sure that every character
	    // leading up to it is a valid scheme character
	    for (int i = 0; i < colonPos; i++) {
		    if (VALID_SCHEME_CHARS.indexOf(url.charAt(i)) == -1) {
			    return false;
		    }
	    }
	    return true;
    }
public static boolean isAbsoluteUrl(final String url) {
	    if (url == null) {      	    // a null URL is not absolute
		    return false;
	    }
	    int colonPos;                   // fast simple check first
	    if ((colonPos = url.indexOf(':')) == -1) {
		    return false;
	    }

	    // if we DO have a colon, make sure that every character
	    // leading up to it is a valid scheme character
	    for (int i = 0; i < colonPos; i++) {
		    if (VALID_SCHEME_CHARS.indexOf(url.charAt(i)) == -1) {
			    return false;
		    }
	    }
	    return true;
    }
Returns <code>true</code> if current URL is absolute, <code>false</code> otherwise.