java: unclosed character literal

                                    In Java, single quotes can only take one character, with escape if necessary. You need to use full quotation marks as follows for strings:

y = "hello";
You also used

System.out.println(g);
which I assume should be

System.out.println(y);
Note: When making char values (you'll likely use them later) you need single quotes. For example:

char foo='m';