How can I find duplicate lines among files?

I have a software module which contains some files with same pattern. private static final long serialVersionUID = \dL; How can I find files with the same value?

$ grep -R serialVersionUID
./path/to/Some.java:    private static final long serialVersionUID = 111L;
./path/to/Other.java:        private static final long serialVersionUID = 222L;
./path/to/Another.java:        private static final long serialVersionUID = 111L;

Not that different preceding indent between columns. Now I want find those files with same value in the second column(private static final ...)?

$ grep -R serialVersionUID | .....
./path/to/Some.java:    private static final long serialVersionUID = 111L;
./path/to/Another.java:        private static final long serialVersionUID = 111L;

Thanks. This is all I could find, so far...

$ grep -R serialVersionUID | sed 's/[ ][ ]*/ /g' | sort -k 2

I have an improvement, yet it prints the second column only.

$ grep -R serialVersionUID | sed 's/[ ][ ]*/ /g' | sort -k 2 | uniq -f 2 -d