Memory is nothing to do with signed or unsigned bit as there is no negative memory address. What is maximum heap size for 32 bit JVM? But this is wrong. If you also have similar confusion on JVM maximum heap space no matte r whether its for your own Java application or any Java web or application server like Tomcat, JBoss or WebLogic, This discussion applies to all of them.
Here is list of some confusions I have seen on Java programmers regarding maximum heap space of 32 and 64 bit Java Virtual Machines. In this Java article, I have collected some of the frequently asked questions around maximum heap space on both 32 and 64 bit JVM and tried to explain them. There could be many different reason why maximum heap space for JVM is less than there theoretical limit and vary from one operating system to other e.
Can anyone help me out with this issue? What is XMs - XMx - How to control Java heap size (memory) allocation While i trying to extends jvm memory in tomcat multiple instance tomcat 7 ,startup. I have a big doubt am using java 32 bit on a 64 bit operating server. But in question 5 you have mentioned that OS will use swap memory in harddisk if it crosses the heap memory size. I have doubt from the question 2 you have mentioned that Java runs out of memory if xmx is mb in windows. Ofcourse, this is only work if you don't have a memory leak, otherwise no mater how much memory you allocate, you will eventually run out with it after some time. If you want to get rid of OutOfMemoryException, one immediate thing you can do is to switch to a bit JVM, that will allow you to allocate more memory than your bit JVM and can handle capacity better. Can somebody say how much and why? What is the maximum memory limit for a 64 bit JVM? Also I heard that Java Garbage Collectors are not optimized for large heap sizes? Considering that in mind, How much maximum heap size should be without compromising performance? How to reduce java heap space out of memory exception Java heap space is already set to max. One quick way to use more heap on a multi-threaded java app is to reduce your Xss.
Now this default thread-stackspace Xss is different on different operating systems and hence the difference between total memory youcan allocate to heap. The threads created by your java process have their own stackspace and that also has to fit into this 4GB limit normally due to OS overhead this limit is 3. A very important point about why you cannot allocate 4GB an only allocate a lot less than 4GB to a java process on a bit machine.