Error java.io

package java.io;

public class fileDir {
	public static void main(String[] args) {
		try {
			File delDir = new File("MyDir");
			delDir.mkdir();
			File delFile1 = new File("MyFile1.txt");
			delFile1.createNewFile();

			File delFile2 = new File(delDir, "MyFile2.txt");
			delFile2.createNewFile();

			delFile1.delete();
			System.out.println("Deletar diretorio: " + delDir.delete());
			
			File newnome = new File(delDir,"newNome.txt");
			delFile2.renameTo(newnome);
			
			File newDir = new File("newDir");
			delDir.renameTo(newDir);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

java.lang.SecurityException: Prohibited package name: java.io
	at java.lang.ClassLoader.preDefineClass(Unknown Source)
	at java.lang.ClassLoader.defineClass(Unknown Source)
	at java.security.SecureClassLoader.defineClass(Unknown Source)
	at java.net.URLClassLoader.defineClass(Unknown Source)
	at java.net.URLClassLoader.access$000(Unknown Source)
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Exception in thread "main"