• Older versions of java used io methods and new ones use java.nio
• We can convert from java.io to java.nio like we are doing with a File below
• Please note that just like paths the file name we pass in File constructor does not have to exist until we use it. and even then it is sometimes ok when file does not exist when using with streams as in that case the file will then be created
• we can convert a java.io File instance to Path instance as below.

   File file = new File("C\\Examples\\file1.txt");
    Path covertedPath = file.toPath();
    System.out.println("The converted path is " + covertedPath);

• Now once we got path object we can then use it with all java.nio methods.Like we can use path.resolve method that takes part of path and results in relative to another path instance
• We can do the same using File class but we can only do that when object of file is created using the version of constructor that takes the file and String as parameter or the extracted version that takes two Strings

  File parent = new File("C:\\Examples");
 //so here we created instance of parent that is use to invoke the resolve method
  // and we pass it as argument to new File and child part of file as other parameter
  File resolvedFile = new File(parent, "dir\\file.txt");
 // and we use resolvedFile method to get the path
  System.out.println("The resolved path is " + resolvedFile.toPath());

Another way of doing it is like below. Here we are passing both parent and child as String and we get same results

   resolvedFile = new File("C:\\Examples", "dir\\file.txt");
  System.out.println("The resolved path is " + resolvedFile.toPath());

Both methods used above are also equivalent to doing something like below

    Path parentPath = Paths.get("C:\\Examples");
    Path childRelativePAth = Paths.get("dir\\file.txt");
    System.out.println("The resolved path is " + parentPath.resolve(childRelativePAth));

I/o methods to rename and delete files are File.renameTo() and File.delete()

• Now we know we have used Path copyPath = FileSystems.getDefault().getPath to get current working directory.
• But when we are working with java.io we have to use File instance and not paths so there are many drawbacks to get working directory that is why java.nio is much better than java.io when working with paths.
• But there is a hack for java.io to get current Working directory

   File workingDirectory = new File("").getAbsoluteFile();
   System.out.println("The current working directory is "+workingDirectory.getAbsolutePath());

• The reason above method works is when we pass empty String to File constructor it translates it to current directory for us which is working directory for us
• Another difference between java.io and java.nio methods is the way they list contents of directory for us
• We have seen when working with nio we use directory streams but when we work with io we use file.list and file.listFiles method
• These methods do the same thing but list method returns an array of String and listFile method returns array of files
• We can also pass an optional filtering parameter to that method Please note the below method will only print one level deep that is it will print Dir3 but not anything inside Dir3. For printing contents inside Dir3 we use walkFileTree methods in java.nio package.

   File dir2File =  new File(workingDirectory,"\\FileTree1\\Dir2");
   String[] dir2Contents =   dir2File.list();
   for(int i = 0;i<dir2Contents.length;i++){
       System.out.println("i="+i+" : "+dir2Contents[i]);
   }

Now lets do the same using listFiles method. This method will also only print one level deep that is it will print Dir3 but not anything inside Dir3.

    File[] dir2Files =  dir2File.listFiles();
    for(int i = 0;i<dir2Files.length;i++){
    //only major difference in list and listFiles method is here we are using getName
    //method to print and it returns the last segment of filePath which in case in the file name
    System.out.println("i="+i+" : "+dir2Files[i].getName());
   }

We should use java.nio methods when working with FileSystems ,but when it is reading and writing file contents sometimes java.io is better choice