/opt/jdk1.7.0_07 の場合
/opt の場合も軽く動作確認しました。
sudo update-alternatives --install "/usr/bin/java" "java" "/opt/jdk1.7.0_07/bin/java" 1 sudo update-alternatives --install "/usr/bin/javac" "javac" "/opt/jdk1.7.0_07/bin/javac" 1 sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/opt/jdk1.7.0_07/bin/javaws" 1