What does the "Multiple markers" mean?

Question

I am trying to use sets in the following way:

static Set<String> languages = new HashSet<String>();
languages.add("en");
languages.add("de");

And I get the following error message generated by Eclipse:

> Multiple markers at this line
>   - Syntax error on token ""en"", delete this      token
>   - Syntax error on token(s), misplaced    construct(s)

I cannot figure out what I am doing wrong. Can anybody please help me?

Solution 1

"Multiple markers" just means "there's more than one thing wrong with this line".

But the basic problem is that you're trying to insert statements directly into a class, rather than having them in a constructor, method, initializer etc.

I suggest you change your code to something like this:

static Set<String> languages = getDefaultLanguages();

private static Set<String> getDefaultLanguages()
{
    Set<String> ret = new HashSet<String>();
    ret.add("en");
    ret.add("de");
    return ret;
}

Solution 2

This means on a single line you are getting multiple errors.

The pic below describes the best. Refer @Jon Skeet to know how to resolve these errors.

.

Solution 3

You are doing something illegal:

Either this (if your code is at class level):

// field definition on class level
static Set<String> languages = new HashSet<String>();
// statements are not allowed here, the following lines are illegal:
languages.add("en");
languages.add("de");

or this:

private void foo(){
    // static keyword not legal inside methods
    static Set<String> languages = new HashSet<String>();
    languages.add("en");
    languages.add("de");

}

Instead, you could use a static initializer to initialize your set:

static Set<String> languages = new HashSet<String>();
static{
  languages.add("en");
  languages.add("de");
}

Comments

[Roman]

thank you for the answer. However, I do not understand it. What you mean by "insert statements directly into a class". What would be the correct syntax?

[Jon Skeet]

@Roman: Correct syntax for what? You just can't do what you were trying to do - statements can't be included directly in a class declaration; they have to be in initializers etc. That's why I've provided a method to create the set and populate it, and then called that method from the variable declaration.

[Roman]

thanks. Now I got what you mean. I could set values for static integer variable without usage of private static. And I just assumed that I can work with maps in the way I work with integers. But, because of some unknown to me reasons, I cannot. But it's OK. I just use private static. Thanks.

[Jon Skeet]

@Roman: No, it's nothing to do with integers in particular. It's not clear to me what you were doing before, but if you didn't have "static" on a variable declaration, then it wasn't a static variable...