A function that copies data from input to output (in Kotlin and Java)

copyBytes.java

void copyBytes(InputStream input, OutputStream output) throws IOException {
  
    //Creating byte array for copying the data
    byte[] buffer = new byte[1024];
    int length = input.read(buffer);

    //Transferring data
    while (length != -1) {
        output.write(buffer, 0, length);
        length = input.read(buffer);
    }
  
    //Finalizing
    output.flush();
    output.close();
    input.close();
}

CopyBytes.kt

//A Kotlin object (singleton) that handles the copying with mulitple different arguments
object CopyBytes {
    @Throws(IOException::class)
    fun copy(input: InputStream, output: OutputStream) {

        //Creating byte array
        val buffer = ByteArray(1024)
        var length = input.read(buffer)

        //Transferring data
        while(length != -1) {
            output.write(buffer, 0, length)
            length = input.read(buffer)
        }

        //Finalizing
        output.flush()
        output.close()
        input.close()
    }

    //In - String, Out - Stream
    fun copy(input: String, output: OutputStream) {
        copy(FileInputStream(input), output)
    }

    //In - Stream, Out - String
    fun copy(input: InputStream, output: String) {
        copy(input, FileOutputStream(output))
    }

    //In - String, Out - String
    fun copy(input: String, output: String) {
        copy(FileInputStream(input), FileOutputStream(output))
    }
}

copyBytes.kt

@Throws(IOException::class)
fun copyBytes(input: InputStream, output: OutputStream) {
  
    //Creating byte array
    val buffer = ByteArray(1024)
    var length = input.read(buffer)

    //Transferring data
    while(length != -1) {
        output.write(buffer, 0, length)
        length = input.read(buffer)
  }

    //Finalizing
    output.flush()
    output.close()
    input.close()
}