(Java) Convert a File's Character Encoding from UTF-8 to UFT-8-BOM

To add a utf-8 BOM to a file is just a matter of prepending these 3 bytes to the file: 0xEF 0xBB 0xBF.

This may be difficult in some programming languages, or it may be trivial in either. Therefore, the Chilkat solution you see here might be helpful, or in a language such as C++, the Chilkat solution isn't really necessary because it's easy to do yourself.

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkCharset charset = new CkCharset();

    charset.put_FromCharset("utf-8");
    charset.put_ToCharset("bom-utf-8");

    boolean success = charset.ConvertFile("qa_data/txt/helloWorld.txt","qa_output/helloWorldBom.txt");
    if (success != true) {
        System.out.println(charset.lastErrorText());
        return;
        }

    System.out.println("Success.");
  }
}