Renaming a file and Repeat a char for the specified number of times from java programing

In java programing you do this code and do some task is completed as like renaming a file from java and Repeat a char for the specified number of times from java program.

Renaming a file from java source code

import java.io.*;

    public class Rename {
         public static void main(String[] argv) throws IOException {
        
         // Construct the file object. Does NOT create a file on disk!
         File f = new File("Rename.java'"); // backup of this source file.
        
         // Rename the backup file to "junk.dat"
         // Renaming requires a File object for the target.
         f.renameTo(new File("junk.dat"));
     }
}

Repeat a char for the specified number of times from java program

public class Test1

    {

     public static void main(String args[])

         {

         String ht = repeat('X',7);

         System.out.println(ht);

     }

    

     public static String repeat(char c,int i)

         {

         String tst = "";

         for(int j = 0; j < i; j++)

             {

             tst = tst+c;

         }

         return tst;

     }

}