Although I check with commands in terminal
strings /usr/lib/x86_64-linux-gnu/libstdc++.so.6 | grep GLIBC
which shows version GLIBCXX_3.4.15 exists, MATLAB still repeats this error. After googling, I found that MATLAB searches the libraries firstly within its own library path /usr/local/MATLAB/R2012a/bin/glnxa64/ or /usr/local/MATLAB/R2012a/sys/os/glnxa64 and then the system library path. The build-in library is somehow out-of-date, and the version GLIBCXX_3.4.15 doesn’t exist in the old library.
I tried to rename the build-in library into another name so that MATLAB can be forced to find the correct one, but there still many other candidates library files with the same name which are prior in the searching order. I need to rename all these old libraries with the same name to help MATLAB direct to correct one, which would be troublesome.
Finally, I found an easy way to solve the problem by linking the correct library file with the MATLAB firstly searched old library file, i.e.,
sudo ln -sf /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16 /usr/local/MATLAB/R2012a/bin/glnxa64/libstdc++.so.6
After running this command in my terminal, the world calms down.