copy the code below and past it in /usr/sbin/ with the name add-apt-repository.

#!/bin/bash
if [ $# -eq 1 ]
NM=`uname -a && date`
NAME=`echo $NM | md5sum | cut -f1 -d" "`
then
  ppa_name=`echo "$1" | cut -d":" -f2 -s`
  if [ -z "$ppa_name" ]
  then
    echo "PPA name not found"
    echo "Utility to add PPA repositories in your debian machine"
    echo "$0 ppa:user/ppa-name"
  else
    echo "$ppa_name"
    echo "deb http://ppa.launchpad.net/$ppa_name/ubuntu lucid main" >> /etc/apt/sources.list
    apt-get update >> /dev/null 2> /tmp/${NAME}_apt_add_key.txt
    key=`cat /tmp/${NAME}_apt_add_key.txt | cut -d":" -f6 | cut -d" " -f3`
    apt-key adv --keyserver keyserver.ubuntu.com --recv-keys $key
    rm -rf /tmp/${NAME}_apt_add_key.txt
  fi
else
  echo "Utility to add PPA repositories in your debian machine"
  echo "$0 ppa:user/ppa-name"
fi

then:

chmod o+x /usr/sbin/add-apt-repository 
chown root:root /usr/sbin/add-apt-repository

now by doing this you will no longer get errors:

add-apt-repository ppa:ferramroberto/java