New to Eclipse, weird error messages

[Dean_Grobler]

Hi there,

I've just switched to Eclipse. I've been using TextPad so Eclipse is pretty cool..
But I've been getting weird error messages that I don't understand/not used to.
Here they are:

JButton btnEnter = new JButton("Enter");
		btnEnter.addActionListener(this);

Here the Error says: Multiple markers at this line.
-Syntax on token "this", delete this token.
-Syntax error on token(s), misplaced construct(s).

What the hell?

And I also had to declare this (below) otherwise Eclipse got all cocky saying that I should.

static final long serialVersionUID;

What is this and why did I have to declare this?

Thanks for taking a look at this..

[JamesCherrill]

Is line 2 part of a method? (it should be)

the dreaded serialVersionUID is because the API says any Serializable class should declare a version number so that if serialization changes you will know which version was serialised when you try to de-serialise it. Eclipse is just picking up every low-level warning that a default stand-alone compile may suppress. Just let it put the version variable in and don't worry.

[masijade]

Just let it put the version variable in and don't worry.

Just remember, however, that if the interface of the class changes (i.e. new public/protected methods, etc) to change that number or you will have problems if the class is actually serialised as part of the app.

[Dean_Grobler]

Is line 2 part of a method? (it should be)

Aww crap, no it's not. It's under class level. Such a dumb mistake. I should remember that one can only declare/initialize under class level. Not work with the methods.(correct me if I'm wrong)

Otherwise thank you both for your help!