I’m trying to understand What the concepts of young, old and permanent generations are in the Java heap terminology, and more specifically the interactions between the three generations. My questions are: What is the young generation? What is the old generation? What is the permanent generation? How does the three generations interact/relate to each other? … Read more
Today I ran my script for filesystem indexing to refresh RAID files index and after 4h it crashed with following error: [md5:] 241613/241627 97.5% [md5:] 241614/241627 97.5% [md5:] 241625/241627 98.1% Creating missing list… (79570 files missing) Creating new files list… (241627 new files) <— Last few GCs —> 11629672 ms: Mark-sweep 1174.6 (1426.5) -> 1172.4 … Read more
If I omit the -Xmxn option from the Java command line then a default value will be used. According to Java documentation “the default value is chosen at runtime based on system configuration” What system configuration settings influence the default value? 10 s 10 On Windows, you can use the following command to find out … Read more
I am writing a client-side Swing application (graphical font designer) on Java 5. Recently, I am running into java.lang.OutOfMemoryError: Java heap space error because I am not being conservative on memory usage. The user can open unlimited number of files, and the program keeps the opened objects in the memory. After a quick research I … Read more
This question may sound fairly elementary, but this is a debate I had with another developer I work with. I was taking care to stack allocate things where I could, instead of heap allocating them. He was talking to me and watching over my shoulder and commented that it wasn’t necessary because they are the … Read more
I get this error message as I execute my JUnit tests: java.lang.OutOfMemoryError: GC overhead limit exceeded I know what an OutOfMemoryError is, but what does GC overhead limit mean? How can I solve this? 22 s 22 This message means that for some reason the garbage collector is taking an excessive amount of time (by … Read more
I stumbled upon Stack Overflow question Memory leak with std::string when using std::list<std::string>, and one of the comments says this: Stop using new so much. I can’t see any reason you used new anywhere you did. You can create objects by value in C++ and it’s one of the huge advantages to using the language. … Read more
Programming language books explain that value types are created on the stack, and reference types are created on the heap, without explaining what these two things are. I haven’t read a clear explanation of this. I understand what a stack is. But, Where and what are they (physically in a real computer’s memory)? To what … Read more
Could not reserve enough space for object heap
