Find the many version of software – like Java installed with "alternatives" on linux

alternatives --config java
+  1        /usr/lib/jvm/jre-1.6.0-openjdk/bin/java
*  2        /etc/alternatives/java_sdk/bin/java
3           /usr/lib/jvm/jre-1.5.0-gcj/bin/java
4           /usr/java/latest/bin/java
5           /usr/java/jdk1.7.0/bin/java