Determining whether a user entered string is a relative or an absolute path

private static boolean isRelative(String path) {
    //return true if the path is relative, false if it is absolute
}

...

String path = getUserEnteredPath();
if ( isRelative(path) ) {
     //append an environment variable to the path before we use it
} else {
     //utilize the path in its current form
}
...

	private static String formatPath( String p ) {
		
		File absoluteFile = null;
		File relativeFile = null;
		
		
		absoluteFile = new File(p);
		
		String relativeFileName = ENV_VAR + SEP_CHAR + p;
		relativeFile = new File(relativeFileName);
		
		String path = "";
		
		if (absoluteFile.exists()) {
			//TODO use absolute file path
			path = absoluteFile.getAbsolutePath();
			System.out.println("Absolute: " + path);
		} else if (relativeFile.exists()) {
			//TODO use relative file path
			path = relativeFile.getAbsolutePath();
			System.out.println("Relative: " + path);
		} else {
			//TODO throw exception
			System.out.println("File could not be resolved");
		}

...
		
	}