If you want to increase your heap space, you can use java -Xms<initial heap size> -Xmx<maximum heap size> on the command line. By default, the values are based on the JRE version and system configuration. You can find out more about the VM options on the Java website. However, I would recommend profiling your application … Read more
No, the difference between stack and heap isn’t performance. It’s lifespan: any local variable inside a function (anything you do not malloc() or new) lives on the stack. It goes away when you return from the function. If you want something to live longer than the function that declared it, you must allocate it on … Read more
If you used Aptitude (apt-get) to install Jenkins on Ubuntu 12.04, uncomment the JAVA_ARGS line in the top few lines of /etc/default/jenkins: # arguments to pass to java #JAVA_ARGS=”-Xmx256m” # <–default value JAVA_ARGS=”-Xmx2048m” #JAVA_ARGS=”-Djava.net.preferIPv4Stack=true” # make jenkins listen on IPv4 address
Your array is allocated on the heap, and the ints are not boxed. The source of your confusion is likely because people have said that reference types are allocated on the heap, and value types are allocated on the stack. This is not an entirely accurate representation. All local variables and parameters are allocated on … Read more
There are two ways to think about your phrase “application heap size available”: How much heap can my app use before a hard error is triggered? And How much heap should my app use, given the constraints of the Android OS version and hardware of the user’s device? There is a different method for determining … Read more
Sampling means taking lots of thread dumps and analyzing stack traces. This is usually faster, does not require runtime changes in your bytecode (which may break it), but is also less accurate. Profiling means instrumenting your classes and methods, so they “report” whenever they are run. This is more accurate, as it counts every invocation … Read more
The on-heap store refers to objects that will be present in the Java heap (and also subject to GC). On the other hand, the off-heap store refers to (serialized) objects that are managed by EHCache, but stored outside the heap (and also not subject to GC). As the off-heap store continues to be managed in … Read more
A similar question was asked, but it didn’t ask about statics. Summary of what static, heap, and stack memory are: A static variable is basically a global variable, even if you cannot access it globally. Usually there is an address for it that is in the executable itself. There is only one copy for the … Read more
Setting unused pointers to NULL is a defensive style, protecting against dangling pointer bugs. If a dangling pointer is accessed after it is freed, you may read or overwrite random memory. If a null pointer is accessed, you get an immediate crash on most systems, telling you right away what the error is. For local … Read more
Here’s what Oracle’s documentation has to say: By default the heap dump is created in a file called java_pid.hprof in the working directory of the VM, as in the example above. You can specify an alternative file name or directory with the -XX:HeapDumpPath= option. For example -XX:HeapDumpPath=/disk2/dumps will cause the heap dump to be generated … Read more