java.util.Scanner Object Declaration not Allowed Here

Question

I have to use Scanner objects in different scopes as presented below:

public String fidentifier (String u)
{
    try {
        Scanner t = new Scanner( new File( "ubasic.dat") );
        //Some Statements
    } catch( FileNotFoundException e ){
            System.out.println( "Exception : " + e );
    }
}

public String didentifier(String cat)
{
    try {
        if( cat.equals("Government") )
                Scanner s = new Scanner( new File("ugov.dat") );
        else
              Scanner s = new Scanner( new File("uhc.dat") );
        //Some Statements
    } catch( FileNotFoundException e ) {
            System.out.println( "Exception : " + e );
    }
}

As I clearly declared Scanner objects in two different methods, I am still getting error pointing out that Scanner object declaration is not allowed in method didentifier().

Point me out where I'm wrong.

Make a [mcve] and [ask], you can't have that error with what you posted... — Tunaki, Apr 16 '16 at 17:59
You can't have that `if` statement with the two scanner things. SImply just do... `Scanner s;` and then inside the if statements do `s = new Scanner(...);` — 3kings, Apr 16 '16 at 18:06
@Tunaki If you are asking for statements written after the comment `//Some Statements`, then these Scanner objects are reading lines from the file and the read line is then split with a delimiter to check for individual Strings. — Ritwik Jamuar, Apr 16 '16 at 18:09

ΦXocę 웃 Пepeúpa ツ · Accepted Answer · 2016-04-16T18:21:48.073

You can use and declare as much Scanners as you want...(it is a bad practice but there is not technical limitation for that...)

...Point me out where I'm wrong....

The error is: Scanner cannot be resolved to a variable The reason of the error is that you are trying to declare an object in a if else scope but no are using curly braces { }

replace the code in the method for this:

if (cat.equals("Government")) {
    Scanner s = new Scanner(new File("ugov.dat"));
} else {
    Scanner s = new Scanner(new File("uhc.dat"));
    // Some Statements
}

and everything will work fine...

at the end you can have one global Scanner object and you just can change the reference of the object.

public String didentifier(String cat)
{
    try
    {
        if( cat.equals("Government") )
              s = new Scanner( new File("ugov.dat") );
        else
              s = new Scanner( new File("uhc.dat") );
        //Some Statements
    }catch( FileNotFoundException e ) {
            System.out.println( "Exception : " + e );
    }
//your Return here...
}

score 0 · Answer 2 · answered Apr 16 '16 at 18:17

The statement after an if has it's own scope. It doesn't make sense to declare a variable which doesn't exist on the next line as it is out of scope. The simplest thing to do is to use a variable or ?:

String file;
if( cat.equals("Government") )
     file = "ugov.dat";
else
     file = "uhc.dat";
Scanner s = new Scanner( new File(file) );

or

Scanner s = new Scanner( new File(cat.equals("Government") ? "ugov.dat": "uhc.dat" ) );

java.util.Scanner Object Declaration not Allowed Here

2 Answers2