The java applet is applet which are in the web browser as most of content can’t be alone accessed by the html so it is necessary to have such applets in the browser although it requires a java plug in.

Learning java
There are lot of benefits to learn java language as one could be a programmer and compile whole new software using the java language and even the java programmers have lot of job opportunities in their field making java a must learning language which is quite flexible too, though it would be advisable to go to java tutorial. Although the java tutorials are quite expensive it would be quite helpful for you to get assistance over java language as at first it could be quite cumbersome to study java language though it starts getting easier day by day
Java applets vs java script
The use of java applets are initiated by the user whereas the use of JavaScript may not be initiated by the user and the java applet is that java programming language that runs in a web browser and also does require a plug in, the java applets are quite good as they are not coded when compared to JavaScript
Types of java applet
The various types of java applets are unsigned applets, signed applets and self-signed applets. The unsigned applets generally don’t come up the security as it could download virus most of the time leading your computer to risks as it comes up with limited usage and even the accessibility of such an unsigned version is quite limited. The signed version is quite better when compared to an unsigned version of applet as the accessibility provided to the user is not that limited and the security of your computer also maintained, although the signature mentioned in the web browsers should be verified once by the browser. There is also a self-signed version where the company manufacturing the applet itself provides their signature on the applet giving the security from their end to the user
Scope of java
The scope for java programming language is quite good in fact learning java would be quite an important part of your as it you the controls of a programme which can be wholly designed by you, it kind of fun to play with the technology by creating the applications what you want and you can even sale some applications online to other application manufacturers