Rename a file using Java

Question

Can we rename a file say test.txt to test1.txt ?

If test1.txt exists will it rename ?

How do I rename it to the already existing test1.txt file so the new contents of test.txt are added to it for later use?

Answer 1

Copied from http://exampledepot.8waytrips.com/egs/java.io/RenameFile.html

// File (or directory) with old name
File file = new File("oldname");

// File (or directory) with new name
File file2 = new File("newname");

if (file2.exists())
   throw new java.io.IOException("file exists");

// Rename file (or directory)
boolean success = file.renameTo(file2);

if (!success) {
   // File was not successfully renamed
}

To append to the new file:

java.io.FileWriter out= new java.io.FileWriter(file2, true /*append=yes*/);