Java（netbeans）为什么这会给我一个非法的类型开始？

Question

全新的Java netbeans） 为什么这会给我一个非法的类型开始？

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package doccentertestingencryption;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author dbarry
 */
public class FileLoader {
    public class ClassLoaderDemo {

        String Foo = "bar";
        try {
            ClassLoader classLoader = ClassLoaderDemo.class.getClassLoader();
            if (classLoader != null) {
                InputStream is = classLoader.getResourceAsStream("mesh.xml");
                BufferedReader br = new BufferedReader(new InputStreamReader(is));
                String s = "";
                try {
                    while ((s = br.readLine()) != null)  {
                        System.out.println(s);
                    }
                } catch (IOException ex) {
                    Logger.getLogger(FileLoader.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}