New to Java Using Eclipse for a class with only C# programming in the past

I'm in a Java programming class.  Pretty basic for most of you guys.  I've only done C# programming in the past.  Pretty new to programming to start with anyway.  Already getting errors on the following program.  Trying to us the \n to start the next line.  Something I never did in C#.  Here is a look at my code and the errors I get.  Does anybody know a good began-er book with sample codes ? I work better by seeing examples.  Thanks please tell me what I'm missing here.

 String radius; //radius entered by user
        double radius1; // converted user input
             
        //get radius from user
        radius = JOptionPane.showInputDialog("Enter the Radius");
        //convert numbers from string to type Double
        radius1 = Double.parseDouble(radius);
     
        JOptionPane.showMessageDialog(null,  "The Diameter Is " +      (2*radius1)"\nThe Circumference Is "
       + (2 * Math.PI * radius1) " \nThe Area Is " + (Math.PI * radius1 * radius1));



When I separate I get it to work, but my lab is to have all in one display box.
This works but .....
 String radius; //radius entered by user
        double radius1; // converted user input
       
        //get radius from user
        radius = JOptionPane.showInputDialog("Enter the Radius");
        //convert numbers from string to type Double
        radius1 = Double.parseDouble(radius);
     
        JOptionPane.showMessageDialog(null,"The Diameter Is " + (2*radius1));
        JOptionPane.showMessageDialog(null,"\nThe Circumference Is "+ (2 * Math.PI * radius1));
        JOptionPane.showMessageDialog(null, " \nThe Area Is " + (Math.PI * radius1 * radius1));