Database Reference
In-Depth Information
Young generation
Young generation memory space is used whenever we create objects in Java. That
is why the young generation memory space is also known as new space. The Java
objects enter the young generation space and they either get the garbage collected
or move into the tenured generation space. Usually the young generation memory
space is smaller than the tenured generation space, therefore it has shorter collec-
tion times as compared to the full GC in tenured space. The garbage collection pro-
cess in the young generation is known as
Minor Garbage Collection
(
minorGC
).
Tenured generation
The Java objects in the tenured generation space last longer than the young gener-
ation space. Usually, the tenured generation memory space is bigger than the young
generation space and it takes more time as compared to minor garbage collection
occurring in the young generation. The garbage collection process in the tenured
generation is known as
Major Garbage Collection
(
majorGC
).
Permanent generation
Permanent generation holds the data needed by VM to describe objects (describing
classes and methods). It is recommended that we always allocate enough perman-
ent generation space to load Oracle SOA Suite library classes in a JVM. The de-
fault permanent generation size is not sufficient for Oracle SOA Suite. There is no
garbage collection process in permanent generation space for a JVM.
Garbage collection tuning
The main objective of garbage collection tuning is to achieve less frequent garbage
collection with less pause time. Tuning the garbage collection process for a JVM is
very important because an application that spends about 10 percent of its time in
