Presentation at ICSME 2015 (Bremen Germany) of an ERA track research article, entitled "Towards a survival analysis of database framework usage in Java projects". Joint work by Tom Mens and Mathieu Goeminne in the context of an F.R.S.-FNRS funded research project carried out at the Software Engineering Lab of the University of Mons, Belgiu

1. Survival
Analysis
of
Database
Technologies
in
Open
Source
Java
Projects
Mathieu
Goeminne,
Tom
Mens
So?ware
Engineering
Lab,
University
of
Mons,
Belgium
hEp://informaHque.umons.ac.be/genlog/projects/disse
ICSME
2015
Early
Research
Achievements
—
Bremen,
Germany,
September
2015

2. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Context
• FNRS
research
project
“Data-­‐Intensive
So?ware
System
EvoluHon”
– Interuniversity
collaboraHon
with
Université
de
Namur
•Expand
empirical
MSR
research
to
include
database-­‐
related
acHviHes
• Overall
goal
– Empirically
analyse
and
support
co-­‐evoluHon
between
program
code
and
database
schema
in
data-­‐intensive
so?ware
systems
• This
paper:
– Study
co-­‐evoluHon
of
Java
ORM
database
technologies

3. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Focus
• Open
source
Java
projects
– Extracted
from
GitHub
Java
Corpus
[Allamanis&SuEon
—
MSR
2013]
– We
considered
13,307
Java
projects
sHll
having
a
Git
repository
in
March
2015
3

4. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Focus
• Many
Java
relaHonal
database
technologies
4

5. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Focus
• Java
relaHonal
database
technologies
5

6. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Focus
• Java
relaHonal
database
technologies
• 19
different
Java
technologies
considered
(of
at
least
3
years
old)
• Detected
by
looking
at
import
statements
and
configuraDon
files
• This
le?
us
with
3,819
Java
projects
6

7. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Focus
• Top
5
technologies
occurred
in
over
200
projects
each
• 3,707
Java
projects
used
(at
least)
one
of
these
5
technologies
7
200

8. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Research
QuesHons
RQ1
Which
combinaHons
of
database
technologies
co-­‐occur
in
the
projects
in
which
they
are
used?
RQ2
How
long
do
database
technologies
survive
in
the
projects
in
which
they
occur?
RQ3
Does
the
introducHon
of
a
technology
influence
the
survivability
of
another
one?
RQ4
How
long
does
it
take
to
introduce
a
second
technology
a?er
a
previous
one
was
introduced?
8

9. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Different
technologies
used
within
the
same
Java
project
(not
necessarily
at
the
same
Hme)
(61%)
RQ1
Which
combinaHons
of
technologies
co-­‐
occur
in
the
projects
in
which
they
are
used?
9
(34,5%)

10. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
RQ1
Which
combinaHons
of
technologies
co-­‐
occur
in
the
projects
in
which
they
are
used?
• How
frequently
do
these
technologies
actually
co-­‐occur?
• Answer:
most
of
the
Hme!
10
t
e
s
”
s
d
e
f
s
k
s
r
a given number of distinct frameworks over their entire history,
and horizontally the maximum number of distinct “co-occurring”
frameworks. Almost all values reside on the diagonal, implying
that in the large majority of all cases (97.5%, i.e., 1213/1273),
different database frameworks used in a project tend to
co-occur.
TABLE II
NUMBER OF PROJECTS INVOLVING A GIVEN NUMBER OF FRAMEWORKS,
OVER THEIR ENTIRE LIFETIME AND IN CO-OCCURRENCE.
# co-occurring fw. ! 1 2 3 4 5
# total # frameworks used
1 2,443
2 22 776
3 2 16 328
4 0 0 18 104
5 0 0 1 1 5
Focusing on specific combinations of frameworks, Table III
reports the number of projects in which two database frame-

11. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
RQ1
Which
combinaHons
of
technologies
co-­‐
occur
in
the
projects
in
which
they
are
used?
• JDBC
co-­‐occurs
with
most
other
technologies
• Spring
and
JPA
co-­‐occur
very
frequently
• Vaadin
occurs
infrequently
with
Hibernate,
JPA,
Spring
11
the other frameworks. 80.1% of all projects that used Hibernate
have also used JDBC in co-occurrence; 48.4% of all projects
that used JPA have used JDBC in co-occurrence; 41.3% of all
projects that used Spring have used JDBC in co-occurrence;
and 39.6% of all projects that used Vaadin have used JDBC
in co-occurrence.
TABLE III
NUMBER OF PROJECTS IN WHICH PAIRS OF DATABASE FRAMEWORKS
CO-OCCUR.
Spring JPA Vaadin Hibernate
JDBC 645 565 143 192
Spring 558 76 156
JPA 98 105
Vaadin 22

12. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
RQ2
How
long
do
database
technologies
survive
in
the
projects
in
which
they
occur?
• Use
staHsHcal
technique
of
survival
analysis
• Kaplan-­‐Meier
esHmator
represents
probability
to
survive
(i.e.,
the
Hme
it
takes
for
a
specific
event
to
occur)
• Takes
into
account
right-­‐censored
data
(e.g.,
the
event
did
not
occur
yet)
12

13. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
RQ2
How
long
do
database
technologies
survive
in
the
projects
in
which
they
occur?
• Most
technologies
tend
to
survive
(>50%
probability)
over
the
project’s
lifeHme
• A
bit
less
for
Vaadin
and
Hibernate
13

14. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
RQ3
Does
the
introducHon
of
a
technology
influence
the
survivability
of
another
one?
• Visually
we
observe
slightly
improved
survival
for
some
combinaHons;
but
staDsDcally
insignificant
14
0 1000 2000 3000 4000 5000 6000
0.00.20.40.60.81.0
C2
C1
A = spring
B = jdbc
0 1000 2000 3000 4000 5000 6000
0.00.20.40.60.81.0
C2
C1
A = jdbc
B = spring

15. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Effect
of
project
size?
• Project
size
and
age
follow
a
log-­‐normal
distribuHon
• How
does
this
affect
the
results?
– Split
projects
in
two
equal
bins
according
to
project
size,
and
compare
results
15
Time
unDl
technology
introducDon
• Technologies
tend
to
be
introduced
at
the
start
of
the
project
• Some
small
projects
also
introduce
technologies
near
the
end
their
observed
lifeHme

16. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
RQ4
How
long
does
it
take
to
introduce
a
second
technology
a?er
a
previous
one
was
introduced?
• Small
projects
are
less
likely
to
introduce
a
second
technology,
and
do
it
later
• JDBC
is
rarely
completed
with
another
technology
• Hibernate
is
o?en
quickly
completed
with
(or
replaced
by)
another
techno
16

17. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Conclusions
• Some
technologies
are
much
more
popular
than
others
– JDBC,
JPA,
Hibernate,
Spring
• Different
Java
database
technologies
tend
to
co-­‐occur
together
– Especially
in
the
larger
Java
projects
• Technologies,
once
introduced,
tend
to
remain
• Introducing
new
technos
does
not
“replace”
exisHng
ones
but
rather
“complements”
them
– Survival
of
exisHng
technologies
is
not
negaHvely
affected
• Big
projects
tend
to
behave
differently
than
small
ones
• Many
technologies
are
used
in
combinaHon
with
JDBC;
but
JDBC
is
also
o?en
used
in
isolaHon
17

18. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
Future
Work
• Analyse
co-­‐occurrence
of
technologies
at
finer
level
of
granularity
• Look
at
NoSQL
database
technologies
• Study
co-­‐evoluHon
between
changes
in
the
source
code
and
changes
in
the
database
schema
• Study
social
aspects
18

19. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
References
• M.
Goeminne,
T.
Mens.
Towards
a
survival
analysis
of
database
framework
usage
in
Java
projects.
ICSME
2015
ERA
track
• M.
Goeminne,
A.
Decan,
T.
Mens.
Co-­‐evolving
code-­‐related
and
database-­‐related
changes
in
a
data-­‐intensive
soQware
system.
CSMR-­‐WCRE
2014
ERA
track
• L.
Meurice,
A.
Cleve.
DAHLIA:
A
visual
analyzer
of
database
schema
evoluDon.
CSMR-­‐WCRE
2014
Tool
Demo
• A.
Cleve,
T.
Mens,
J.-­‐L.
Hainaut.
Data-­‐intensive
system
evoluHon,
IEEE
Computer
43(8):
110-­‐112
(2010)
• A.
Cleve,
M.
Gobert,
L.
Meurice,
J.
Maes,
J.
Weber.
Understanding
database
schema
evoluHon:
A
case
study,
Science
of
Computer
Programming
(2013)
19

20. September
2015
—
InternaHonal
Conference
on
So?ware
Maintenance
and
EvoluHon
(ICSME2015),
Bremen,
Germany
References
X
!
!
Evolving Software Systems
Mens, Tom; Serebrenik, Alexander; Cleve, Anthony (Eds.)
2014, XXIII, 404 p.
!
Springer, ISBN 978-3-642-45398-4