Abstract:
Freshly created objects are a blank slate: their mutable state and their constant
properties must be initialised before they can be used. Programming languages
like Java typically support object initialisation by providing constructor methods.
This thesis examines the actual initialisation of objects in real-world programs to
determine whether constructor methods support the initialisation that programmers
actually perform. Determining which object initialisation techniques are
most popular and how they can be identified will allow language designers to
better understand the needs of programmers, and give insights that VM designers
could use to optimise the performance of language implementations, reduce
memory consumption, and improve garbage collection behaviour.
Traditional profiling typically either focuses on timing, or uses sampling or
heap snapshots to approximate whole program analysis. Classifying the behaviour
of objects throughout their lifetime requires analysis of all program behaviour
without approximation. This thesis presents two novel whole-program
object profilers: one using purely class modification (#prof ), and a hybrid approach
utilising class modification and JVM support (rprof ). #prof modifies programs
using aspect-oriented programming tools to generate and aggregate data
and examines objects that enter different collections to determine whether correlation
exists between initialisation behaviour and the use of equality operators
and collections. rprof confirms the results of an existing static analysis study of
field initialisation using runtime analysis, and provides a novel study of object
initialisation behaviour patterns.
