<s>
A	O
soft	B-General_Concept
reference	I-General_Concept
is	O
a	O
reference	O
that	O
is	O
garbage-collected	O
less	O
aggressively	O
.	O
</s>
<s>
The	O
soft	B-General_Concept
reference	I-General_Concept
is	O
one	O
of	O
the	O
strengths	O
or	O
levels	O
of	O
'	O
non	O
strong	B-General_Concept
 '	O
reference	O
defined	O
in	O
the	O
Java	B-Language
programming	I-Language
language	I-Language
,	O
the	O
others	O
being	O
weak	B-General_Concept
and	O
phantom	B-General_Concept
.	O
</s>
<s>
In	O
order	O
from	O
strongest	O
to	O
weakest	O
,	O
they	O
are	O
:	O
strong	B-General_Concept
,	O
soft	O
,	O
weak	B-General_Concept
,	O
phantom	B-General_Concept
.	O
</s>
<s>
Soft	B-General_Concept
references	I-General_Concept
behave	O
almost	O
identically	O
to	O
weak	B-General_Concept
references	I-General_Concept
.	O
</s>
<s>
Soft	O
and	O
weak	B-General_Concept
references	I-General_Concept
provide	O
two	O
quasi-priorities	O
for	O
non-strongly	O
referenced	O
objects	O
:	O
the	O
garbage	B-General_Concept
collector	I-General_Concept
will	O
always	O
collect	O
weakly	O
referenced	O
objects	O
,	O
but	O
will	O
only	O
collect	O
softly	O
referenced	O
objects	O
when	O
its	O
algorithms	O
decide	O
that	O
memory	O
is	O
low	O
enough	O
to	O
warrant	O
it	O
.	O
</s>
<s>
Soft	B-General_Concept
references	I-General_Concept
may	O
be	O
used	O
,	O
for	O
example	O
,	O
to	O
write	O
a	O
free	O
memory	O
sensitive	O
cache	B-General_Concept
such	O
that	O
cached	O
objects	O
are	O
kept	O
until	O
there	O
is	O
not	O
enough	O
heap	O
space	O
.	O
</s>
<s>
In	O
some	O
cases	O
weakly	O
referenced	O
objects	O
may	O
be	O
reclaimed	O
too	O
quickly	O
to	O
make	O
such	O
a	O
cache	B-General_Concept
useful	O
.	O
</s>
