$ dpkg -l | grep openjdk
ii  openjdk-6-jdk                          6b23~pre11-0ubuntu1.11.10.2             OpenJDK Development Kit (JDK)
ii  openjdk-6-jre                          6b23~pre11-0ubuntu1.11.10.2             OpenJDK Java runtime, using Hotspot JIT
ii  openjdk-6-jre-headless                 6b23~pre11-0ubuntu1.11.10.2             OpenJDK Java runtime, using Hotspot JIT (headless)
ii  openjdk-6-jre-lib                      6b23~pre11-0ubuntu1.11.10.2             OpenJDK Java runtime (architecture independent libraries)
rc  openjdk-7-jdk                          7~b147-2.0-0ubuntu0.11.10.1             OpenJDK Development Kit (JDK)
rc  openjdk-7-jre                          7~b147-2.0-0ubuntu0.11.10.1             OpenJDK Java runtime, using Hotspot JIT