I have a Java application that I run from a console which in turn executes an another Java process. I want to get a thread/heap dump of that child process. On Unix, I could do a kill -3 <pid> but on Windows AFAIK the only way to get a thread dump is Ctrl-Break in the … Read more
It says here that -Xss is used to “set thread stack size”, what does it mean exactly? Could anyone help me understand this? 4 Answers 4
I upgraded to the latest Java 7u40 on MacOS X and started getting the following message on the console when launching my application using Eclipse. The app works fine but I would like to find out the cause of the problem and hopefully a fix for it. objc[10012]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk/Contents/Home/bin/java … Read more
What is the difference between a thread’s context class loader and a normal class loader? That is, if Thread.currentThread().getContextClassLoader() and getClass().getClassLoader() return different class loader objects, which one will be used? 4 Answers 4
Specifically, why would it help to fix a PermGen OutOfMemoryError issue? Also, bonus points for an answer that points me to the documentation on JVM arguments… 3 Answers 3
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I am getting the following exception repeatedly each time I try to run the program. Error occurred during initialization of VM Could not reserve enough space for object heap Could not create the Java virtual machine. I tried to increase my virtual memory (page size) and RAM size, but to no avail. How can I … Read more
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
Many times, a Java app needs to connect to the Internet. The most common example happens when it is reading an XML file and needs to download its schema. I am behind a proxy server. How can I set my JVM to use the proxy ? 19 Answers 19
What is the difference between JVM, JDK, JRE & OpenJDK? I was programming in Java and I encountered these phrases, what are the differences among them? 22 Answers 22
