jvm-hotspot Questions
11
Solved
How do you write (and run) a correct micro-benchmark in Java?
I'm looking for some code samples and comments illustrating various things to think about.
Example: Should the benchmark measure time...
Brack asked 2/2, 2009 at 17:39
1
There are many articles/webpages stating that JRockit will be merged into new version of JVM or JDK 8:
https://en.wikipedia.org/wiki/JRockit
http://www.mythics.com/about/blog/answers-to-common-qu...
Sobranje asked 3/11, 2015 at 1:45
2
Solved
I see references to pre-allocated JVM exceptions there:
- http://www.oracle.com/technetwork/java/javase/relnotes-139183.html
- http://dev.clojure.org/display/community/Project+Ideas+2016
But looki...
Filet asked 8/2, 2017 at 14:5
1
Solved
I am instrumenting a class file during runtime for various purposes. I'm using a JVMTI agent to that end. My strategy to instrument a method is to call RetransformClasses function to invoke ClassFi...
Capernaum asked 23/1, 2017 at 8:6
1
Solved
Currently I have a core-dump file and I would like to extract the heap-dump. Whatever I tried I always get the following error message:
god@heaven:~$ sudo /opt/java-MyApp/bin/jmap -dump:format=b,f...
Johppah asked 20/1, 2017 at 7:27
3
Solved
This question is not about the difference between them - I know what spurious failure is and why it happens on LL/SC. My question is if I'm on intel x86 and using java-9 (build 149), why is there a...
Atalee asked 29/12, 2016 at 14:46
1
Solved
I am working on a Oracle HotSpot and GC internals article, but I am confused about the meaning of OOP (Ordinary Object Pointer).
The Oracle documentation states that an OOP is a 32 or 64 bit point...
Polygyny asked 30/12, 2016 at 20:58
2
Solved
We have a JBoss application server running in Java 6 update 45. We are running into OutOfMemoryErrors that we have most likely introduced ourselves. We'd like to analyze those and want to create a ...
Camerlengo asked 20/6, 2013 at 7:55
1
Solved
While using -XX:+PrintCompilation recently (JDK 8r111) to examine method compilation, I noticed a new column which doesn't appear in the documentation I can find on the topic:
this column
|
|
...
Benniebenning asked 14/12, 2016 at 2:50
2
Somewhat related question, and a year old: Do any JVM's JIT compilers generate code that uses vectorized floating point instructions?
Preface: I am trying to do this in pure java (no JNI to C+...
Haemolysis asked 3/5, 2014 at 22:12
2
Solved
say I have 2 instances of the same class, but they behave differently (follow different code paths) based on a final boolean field set at construction time. so something like:
public class Foo {
...
Sinew asked 8/11, 2016 at 18:22
4
Solved
Can someone please explain what the JVM option ReservedCodeCacheSize and InitialCodeCacheSize are? Specifically when/why would I want to change it? How do I decide what the right size is?
This is ...
Classicize asked 22/9, 2011 at 10:17
6
Solved
I was recently reading about all the JVM arguments available in JRE 6 [Java VM Options] and saw this :
-XX:+StringCache : Enables caching of commonly allocated strings.
Now I was always under ...
Cystectomy asked 26/6, 2009 at 16:14
1
So far I know that:
Objects are allocated in the eden space and if they survive a minor collection they get promoted to one of the survivor spaces
For further minor collections objects' that surv...
Diorio asked 12/3, 2014 at 11:24
2
Solved
I've heard that JIT automatically inlines small methods, like getters (they have about 5 bytes). What is the boundary? Is there any JVM flag?
Hemo asked 12/4, 2016 at 22:31
2
Solved
My question is the following:
Its usual for Java code to have generic collections implemented like:
public class GenericCollection<T> {
private Object[] data;
public GenericCollection ()...
Desultory asked 27/3, 2016 at 23:25
11
Solved
Is there any real practical difference between "java -server" and "java -client"?
All I can find on Sun's site is a vague
"-server starts slower but should run faster".
What are the real d...
Coniine asked 13/10, 2008 at 18:40
1
Solved
As we know, some JIT allows reordering for object initialization, for example,
someRef = new SomeObject();
can be decomposed into below steps:
objRef = allocate space for SomeObject; //step1
ca...
Bal asked 9/3, 2016 at 5:8
2
Solved
I already worked with -XX:+PrintCompilation, and I know the basic techniques of the JIT-compiler and why JIT-compilation is used.
Yet I still have not found out how the JVM decides to JIT-compile ...
Underwing asked 24/2, 2016 at 12:10
1
Solved
I read a few posts about JVM at Stack Overflow and would like to download a binary copy of the Hotspot JVM, yet I am not able to find it on http://www.java.net.
Beside that, what is the difference...
Intorsion asked 19/2, 2016 at 15:15
2
Solved
I just wonder about additional overhead of remote debugging. I start application using HotSpot with these parameters:
-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005
I heard a...
Unroll asked 8/2, 2016 at 11:13
1
Solved
Is there any utility or script, either using java or native code, to see list of all strings present in String Pool in JDK 8 HotSpot JVM, without having lot of performance impact on JVM?
Alternati...
Lauree asked 6/2, 2016 at 8:17
1
Solved
I tried to create benchmarks with JMH and all tutorials i found refer to @GenerateMicroBenchmark.
But i cannot find it in jmh-core:1.11.3.
If it was removed, what is its replacement and what is t...
Gassaway asked 17/1, 2016 at 13:22
1
Solved
In the context of an in-memory database, we are using off-heap memory in conjunction to the G1 collector of hotspot.
However, when off-heap memory usage reaches MaxDirectMemorySize, a full GC is t...
Draughtsman asked 20/11, 2015 at 16:58
3
Solved
Is there a performance difference between using Collections.emptyList() or an empty ArrayList, especially when using a JIT compiler?
I could imagine that - for example - the JIT compiler doesn't d...
Resist asked 24/10, 2015 at 11:37
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