多项选择题 Whicharevalididentifiers？（）

单项选择题 Which method implementations will write the given string to a file named "file"， using UTF8 encoding？（）   IMPLEMENTATION a：   public void write（String msg） throws IOException {   FileWriter fw = new FileWriter（new File（"file"））；   fw.write（msg）；   fw.close（）；   }   IMPLEMENTATION b：   public void write（String msg） throws IOException {   OutputStreamWriter osw =  new OutputStreamWriter（new FileOutputStream（"file"）， "UTF8"）；  osw.write（msg）；   osw.close（）；   }   IMPLEMENTATION c：   public void write（String msg） throws IOException {  FileWriter fw = new FileWriter（new File（"file"））；   fw.setEncoding（"UTF8"）；   fw.write（msg）；   fw.close（）；  }   IMPLEMENTATION d：   public void write（String msg） throws IOException {  FilterWriter fw = FilterWriter（new FileWriter（"file"）， "UTF8"）；   fw.write（msg）；  fw.close（）；   }   IMPLEMENTATION e：   public void write（String msg） throws IOException {   OutputStreamWriter osw = new OutputStreamWriter（  new OutputStream（new File（"file"））， "UTF8"  ）；   osw.write（msg）；   osw.close（）；   }

多项选择题 Given the following code， which code fragments， when inserted at the indicated location， will succeed in making the program display a button spanning the whole window area？（）   import java.awt.*；   public class Q1e65 {   public static void main（String args[]） {   Window win = new Frame（）；   Button but = new Button（"button"）；   // insert code fragment here  win.setSize（200， 200）；   win.setVisible（true）；   }   }