Increasing the xms to the same value as the xmx will avoid delays caused by heap expansion in the application code. If the value of the -Xms parameter is smaller than the value of the -Xmx parameter, than not all of the space that is reserved is immediately committed to the virtual machine. They are common to all JVM garbage collectors. 提供更好的垃圾回收性能 ：将-Xms和. Therefore a value like -Xms128m will set the minimum heap size to 128 MB. However, the -Xms option can be used with all GC policies except for the metronome GC policy because the heap is always fully expanded. Esto elimina las potencialmente costosas reasignaciones de la pila, y puede reducir la cantidad de fragmentación de la pila que puede ocurrir. Exemplo: java -server -Xms100m -Xmx1500m <outros. The Garbage Collector scans the Young Generation very often and after a few sweeps, if those objects are still there then they are moved to Old Generation to free space for new objects. 7. Must be a boolean (either true or false). Let’s get started: Below are the simple steps to change -Xmx / -Xms values or other JVM parameters if you are running Tomcat from command prompt. -Xms and -Xmx simply specifies the range in which the JVM can operate and resize the heap. This option was available prior to JDK. Format: -Xms<size> [g|G|m|M|k|K] -Xmx This option sets the maximum Java heap size. Half the available memory with a minimum of 16 MB and a maximum of 512 MB. Then click on Advanced system settings. Second point is that -Xms controls the committed memory in the virtual space. Enter in the code to allocate more RAM. e. Xmx 是指设定程序运行期间最大可占用的内存大小。. For example -Xms could format your hard drive depending on the VM (it would not - but strictly speaking it could. Xms specifies the initial memory allocation pool on process startup. These are great JVM Arguments for Beefier PC's but if you're using very old hardware (like me) the first one is a better choice for performance and stability. -Xmx is max memory. -Xmn6144m. 第二个线程在Heap不足时,遍历Heap,将Young 区升级为Older区. 系统的可用虚拟内存限制;3. We currently have everything set up to stay within our 1GB guaranteed RAM, but it seems as. ZGC supports heap sizes from 8MB to 16TB. Why does setting the -Xmx too high sometimes cause the JVM to fail, even if there's available RAM? 0. Young generation represents all the objects which have a short life of time. You're setting these two options: -Xms14G -Xmx14G. Nature's Compass - A utility item that allows you to search for any biome's location in the world. but the in-game debug screen shows the memory usage of client. It means that the application can use the maximum heap size of 80M of the available memory. This best practice advice applies to AM, DS, IDM and IG running on Java® 11 (or 17 where supported). Generally, when moving to G1 from other collectors, particularly the Concurrent Mark Sweep collector, start by removing all options that affect garbage collection, and only set the pause-time goal and overall heap size by using -Xmx and optionally -Xms. It means JVM will be started with Xms amount of memory and JVM will be able to use maximum of JVM amount of memory. If -Xms and -Xmx are the same value, then the JVM's heap size will stay constant at that value. PAUSE . Follow the steps given below for setting up the maximum heap size. Java再入門 JVMオプション. -XX:ParallelGCThreads= threads. . -Xms (you didn't set that) is the minimum allocation size. The resulting output is in bytes. -Xms 堆内存的初始大小，默认为物理内存的1/64 -Xmx 堆内存的最大大小，默认为物理内存的1/4 -Xmn 堆内新生代的大小。. 5GB. " 3. Don’t forget to add the word “M” or “G” after specifying the size to indicate Mega or Gig. Consider the following analogy: Imagine you're going to school and you get yourself a single page for taking notes. forge 1. java -Xmx####M -Xms####M -exe Minecraft_Server . "-Xms 6G" - Sets the initial allocated RAM of the Java application (Minecraft) at launch; this value should be the same as the maximum allocated RAM to reduce amount of garbage collection the program has to do. The Xms was increased to give the application a healthy start, and Xmx was significantly raised to accommodate the volume of data during peak times. I have also seen a few people in JellySquid's Hideout say that setting -Xms equal to -Xmx caused performance issues: . That's what you need to change. jar --nogui There should be no space between -Xmx and the value, and -Xms and the value, and no double minus before thee nogui argument. Follow the steps below to allocate more RAM: Open the Minecraft Launcher. If you want to add a MAX amount of RAM Change -Xmx1G to -Xmx and then the number of ram you want and then the unit, so for 512 MB do -Xmx512M and for 8 GB do -Xmx8G. For example, if we want to assign minimum 2 GB and maximum 5 GB to JVM, we need to write: Xmn is the heap size for young generation heap space. Alternatively you can try to switch to G1 garbage collector using -XX:+UseG1GC. Java堆大小设置，Xms 和 Xmx设置为老年代存活对象的3-4倍，即FullGC之后的老年代内存占用的3-4倍 永久代 PermSize和MaxPermSize(元空间)设置为老年代存活对象的1. For previous versions or if the IDE crashes, you can change the value of the -Xmx option manually as described in JVM options. If you click Edit Profile to the left of the Play button, at the bottom of the Profile Editor is a checkbox "JVM Arguments". -Xmx 堆内存的最大大小，默认为物理内存的1/4. ‘-m’) than your heap size value. It keeps the allocated ram for the server only and stop the OS from using this ram. - Committed가 -Xms, MAX가 -Xmx 값인 듯. You can take the GUI flag off if you want a GUI window with performance stats, a player list, and a live view of the server log. 物理内存的1/4 (<1GB) 默认 (MaxHeapFreeRatio参数可以调整)空余堆内存大于70%时，JVM会减少堆直到 -Xms的最小限制. The Z Garbage Collector is enabled with the command-line option -XX:+UseZGC. Options. The line below shows 3 JVM arguments. Generally, when I need more memory for Minecraft, I set the max heap and not the min heap. -Xmx<size>. Porém não era um dos melhores e eu sofri para jogar com mods. This could be the cause of your performance issues. Generally you will never need to set a size or ratio for the Young. It is recommended to reduce your Xmx/Xms by about 1000-1500M to avoid running out of memory or “OOMKiller” hitting your server. The Java heap can never grow larger than -Xmx. บทความวิกิฮาวนี้จะแนะนำวิธีการเพิ่มความจำ (RAM) ที่ Minecraft ใช้ได้ เผื่อจะแก้ memory errors หรือปัญหาความจำไม่พอได้ ถ้าเล่น Minecraft ใน. -Xms is used to set the minimum memory (initial heap), and -Xmx is used to set the maximum memory (maximum heap) allocation. -Xmn is the new space value (which is a different thing, entirely). Oracle 32 bit heap FAQ. 可以利用JVM提供的-Xmn -Xms -Xmx等选项可进行设置。 例如：java -jar -Xmn16m -Xms64m -Xmx128m MyApp. -Xmx specifies maximum memory size for Java virtual machine (JVM), while -Xms specifies the initial memory size. 18, JRE version 17 is required. When tuning GC, you need to collect the GC statistics over a longer period of time and then act on that. Correct: java -Xmx1024m -jar JavaApplication. 17. 一般来讲，大点，程序会启动的快一点，但是也可能会导致机器暂时间变慢。. This means that when you start your program the JVM will allocate this amount of memory instantly. From OpenJ9 release 0. Please help here. When using the balanced GC policy without specifying -Xmn or -Xmns, the GC may decide to shrink eden size below its initial size (25% of -Xms) if it determines that doing so will improve GC performance. This option was deprecated in JDK 8, and superseded by the -XX:MaxMetaspaceSize. By default, the JVM grows or shrinks the heap at each GC to try to keep the proportion of free space to the living objects at each. This range is set as a percentage by the parameters -XX:MinHeapFreeRatio=-XX:MaxHeapFreeRatio=; and the total size bounded by -Xms-Xmx. You can also set the heap size according to your requirement. Briefly, -Xmn decides the size of the young space in a JVM. -Xmn - new space (this is a more specific tuning parameter) For client-side Minecraft, it generally makes sense to set the Xmx and Xms to the same value (-Xmx2G -Xms2G). com Best values for min-max RAM, Xms & Xmx arguments Edit: Solved, just set them both to the same value! So when running my server (which has 8GB or RAM) I set my Xms to 2G (minimum RAM) and Xmx to 6GB (maximum RAM). 一般来讲，大点，程序会启动的快一点，但是也可能会导致机器暂时间变慢。. By doing so, it may assist to. Anyways, it doesn't use much more ram. To edit sto gameserver. Known Issue for Linux Users此值可以设置与-Xmx相同，以避免每次垃圾回收完成后JVM重新分配内存。-Xmn2g ：设置年轻代大小为2G。 整个JVM内存大小=年轻代大小 + 年老代大小 + 持久代大小 。持久代一般固定大小为64m，所以增大年轻代后，将会减小年老代大小。12. I suggest leaving it out and replacing it with -Xincgc instead. alla then ktlv gi ayto m dhmiourgithike to pa. 8. This will create a new text document in the same location as the minecraft_server. ) Some products like Ant or Tomcat might come with a batch script that looks for the JAVA_OPTS environment variable. On a Unix/Linux system, you can do. You can create a desktop shortcut to your Minecraft launcher through the SpecialK UI for even more convenience. STEP 4: To allocate RAM to a Minecraft version, move your mouse over the three dots on the right, CLICK and select Edit. View User Profile. -Xms = initial and minimum java heap. -XX:PermSize: Sets the initial size of the Permanent Generation (perm) memory area. Go to the “Installations” tab. 如果程序运行需要占用更多的内存，超出了这个设置值，就会抛出OutOfMemory异常。. Also, the -Xms value can be used as “minimum heap size” to set a fixed heap size by setting -Xms = -Xmx when, for example, you want to run benchmark tests. 0_29 on Windows 7/32-bit: -Xmx256m -XX:MaxPermSize=64m. edit @Aikar "-Xms matching -Xmx"-Xms is allocated at startup and it will grow up to -Xmx, setting ms == mx effectively turns off this behavior. it all depends on the RAM size, you can extend it max upto RAM size. So, java -Xmx4G -Xms1G -jar. Just one snapshot of Generation size is not enough. . g. UnrecognizedOptionException:. Default xms size is 1/4th of the physical memory size. eclipse. The Xms was increased to give the application a healthy start, and Xmx was significantly raised to accommodate the volume of data during peak times. 减少堆空间调整的频率 ：当-Xmx和-Xms设置为相同的值时，Java虚拟机不需要根据程序的需求动态调整堆空间的大小。. . Create a text document in your server folder. native_memory command. JVM 中最大堆大小有三方面限制：相关操作系统的数据模型（32-bt还是64-bit）限制；系统的可用虚拟内存限制；系统的可用物理内存限制 。. , Xmx2048m which means the maximum heap size of JVM will be 2 GB only. 8GB of RAM is, in most cases, enough for a "default" Server with not like 100 plugins and many many players. Scroll down to "Java Settings" where you'll see "Allocated Memory" with a slider. Note that the Max ram you allocate will be unusable by the rest of your system so there is really no point in setting the Min amount lower. gif: Bye guys!The subreddit for all things related to Modded Minecraft for Minecraft Java Edition --- This subreddit was originally created for discussion around the FTB launcher and its modpacks but has since grown to encompass all aspects of modding the Java edition of Minecraft. NOT AN OFFICIAL MINECRAFT. In JDK 8, The default maximum heap size is. This option was available prior to JDK 8 but is no longer supported. For example;As taken from @dmitripivkine testing, setting -Xmx and -Xmnx $ . Xms/Xmx Set the Least Java can use ( A Minimum) and a MAX it can use. 10+9/bin/java -Xmx4g -Xmn4g -version. -Xmn 2G：设置年轻代大小为2G. For example, starting a JVM like below will start it with 256. Setting -Xms is then unnecessary since the heap size itself is static. Modified 4 years ago. That seems very, very specific to me. -XX:PermSize. Share. If you are using Windows or a desktop-based Linux distribution, you should have at least 1 GB of additional physical RAM in the computer, so the graphics on the desktop don't become laggy. Also Xmn is minimum memory but you don't need to change that. If you monitor your java process with an OS tool like top or. Many options that are useful for other collectors to respond in some particular way, have either no effect at all,. XXMaxPermSize 1024m --launcher. The Xmx switch works with bytes, not fractions. This. . About xmx. Community content is available under CC BY-NC-SA unless. etc. -Xms: Sets the minimum and initial size of the heap. XMX และ Xms Minecraft คืออะไร?. -Xmx specifies maximum memory size for Java virtual machine (JVM), while -Xms specifies the initial memory size. -xmn2g : Set the young generation. I am quite sure my server provider doesn't have the best start parameters. Contrary to popular belief, this doesn’t specify a minimum amount of RAM that the JVM will use. The Java heap can never grow larger than -Xmx. In your . Xmn คือขนาดฮีปสำหรับพื้นที่ฮีปรุ่นใหม่ ออบเจ็กต์ใหม่ถูกสร้างขึ้นในฮีปนี้ Garbage Collector สแกนคนรุ่นใหม่บ่อยมาก. XWiki should be set with very large memory settings, high cache: Set -Xmx (7. I tried Xmx as 3GB (3272 MB) and after that not allowed to define . don't forget to add word "M" or "G" after specifying size to indicate Mega or Gig. pointless to use. -xms3550m : Set the JVM to drive memory to 3550m. I would NOT recommend setting those two numbers to be. e. 8. It is currently using 80% of a 4GB heap and rising a few percent each day. We run a Minecraft server that relies on Java on a vServer that has 1GB guaranteed RAM and 4GB burstable RAM. บทความเกี่ยวกับ : java -Xms , java -Xmx กำหมด memory ให้ JVM เพื่อป้องกันปัญหา Out of Memory หลายคนคงจะเจอปัญหา out of memory เนื่องจากแรมไม่พอให้ JVM ใช้งาน เหตุการแบบนี้อาจะเกิด. In general, keep the eden size between one fourth and one third the maximum. single-player). What is meaning of mx and ms?Note: You can change the amount of memory allocated to your server by changing the values after Xmx and Xms. Step 1: Open the Control Panel and click on the System icon. Remember that the JVM will reserve the amount of memory setted in Xms even if your application don't use them. I know that -Xmx128M means 128 Mebibytes (= 128 * 1024 * 1024 bytes). Tick the box next to 'JVM Arguements'. But don't set it too high. jasotufy2. My statement regarding the use of -Xmn and -Xms came from my own experience with the arguments. 42. To get the most heap possible set XmS to 1024 and XmX to 2048. Virtual space for a 64 bit CPU is huge. IntelliJ IDEA also warns you if the amount of free heap memory after a garbage collection is less than 5% of the maximum heap size: Click Configure to increase the amount of memory allocated by the JVM. bat EDIT by Moderator: merged posts, please use the edit button instead of double posting. -Xmx: This option sets the maximum Java heap size. Thanks! leaving only 1GB for server will probably not be enough, just for the comparison, my server with 6GB allocated in really use around 7. jvmArguments parameter:. Make plenty of memory available to the young generation. Enter -Xmx8G if you want to specify a maximum of 8 GB of RAM to your game. I am kind of confused as my understanding of -Xms (A MB) is that A MBs of memory is allocated to JVM by OS whereas -Xmx (B MBs) means JVM could expand up to B MBs. In this example, we set the initial heap size to 512 megabytes (Xms512m) and. Mods, resource packs or view distances above 16 are the only reasons to make it any bigger though. jar nogui. Since GC occurs when the generations fill up, throughput is inversely proportional to the amount of the memory available. The modified JVM settings:JVM调优总结 -Xms -Xmx -Xmn -Xss (转) Xms 是指设定程序启动时占用内存大小。. This documentation page on the command line arguments says the following applies to all the arguments accepting memory sizes:Semana passada visitei a casa da minha vó e tentei jogar minecraft no pc de lá. -XX:MaxPermSize. UN/LOCODE 2011-2. dgc. Another must read: Change -Xmx value of Tomcat in Eclipse IDE. Now, I would suggest you get MagicLauncher, and allocate more RAM in it, or use the default MC launcher to set the amount of ram you want to allocate in the JVM Arguments. ago. g. Consider the following analogy: Imagine you're going to school and you get yourself a single page for taking notes. answered Aug 25, 2015 at 13:36. When setting the Xms and Xmx values, if your host says you have 8000M memory, DO NOT USE 8000M! Minecraft (and Java) needs additional memory on top of that Xmx parameter. Try to increase -Xmx value. What is xmn in Minecraft, on the other hand, is asked. Auto Refresh - Automatically refreshes your. So for a 1G machine maximum heap size is 256MB 2. But you also need to take into consideration all the other processes running on the machine and their RAM usage. XmnXmsXmxXss有什么区别 Xmn、Xms、Xmx、Xss都是JVM对内存的配置参数，我们可以根据不同需要区修改这些参数，以达到运行程序的最好效果。. They are common to all JVM garbage collectors. Initial java heap size. Select the one you want to change the amount of RAM for, click on the. Format for specifying xms: java -xms {Numerical Size} {Unit. The Java/JVM Xms and Xmx settings should both pre-allocate the amount of memory to start along with the maximum defined value to designate to the Java/JVM instance. Setting Xms and Xmx for standalone Java applications: To set the Xms and Xmx parameters for a standalone Java application, you can specify them as command-line arguments when starting the JVM. There is NEVER a valid reason to run minecraft without the flags, you should just correctly size your Xmx and Xms parameters to the actual memory you have available. In Informatica Intelligent Cloud Services (IICS), to increase Java Xmx setting for Data Integration Service (DIS) Tomcat and Data Transformation Manager (DTM) process, refer to the following Tomcat process: Navigate to Administrator > Runtime Environments. -Xmx 堆内存的最大大小，默认为物理内存的1/4. 这意味着您的JVM将使用 Xms 内存量启动，并且最多可以使用 Xmx 内存量。. xmx is used to specify the upper bound of java heap memory size. This means that the JVM should start with 14 GB (-Xms) and grow to a maximum of 14 GB (-Xmx) heap RAM usage. Closed 3 years ago. 1. To further tune your memory usage. For efficient garbage collection, the -Xmn value should be lower than the -Xmx value. jar tells the JVM to allocate 512MB for heap space when it launches, and it can grow to 2048MB before stopping. JVM. . Your advice is also wrong and detrimental. -XX:MaxGCPauseMillis=200 -XX:ParallelGCThreads=<var> -XX:ConcGCThreads=<var>. 堆内存相关配置. Xms 是指设定程序启动时占用内存大小。. -Xmx specifies the precise upper limit for the heap. Edit: details you asked for. It is recommended to reduce your Xmx/Xms by about 1000-1500M to avoid running out of memory or "OOMKiller" hitting your server. Bên dưới là lượng ram trong con server Linux ở nhà khi chưa chạy gì (276 MB Ram)See Using -X command-line options for more information about the <size> parameter. Xmn、Xms、Xmx、Xss都是JVM对内存的配置参数，我们可以根据不同需要区修改这些参数，以达到运行程序的最好效果。. Improve this answer. order of the flags doesn't matter, so long as they're before -jar whatever. x, you'll immediately have this JVM arguments defaulted when launching. What to set depend on your application and your hardware. Vậy nên để xmx = xms. Attachments. The size of the space reserved can be specified with the -Xmx option. 如果程序运行需要占用更多的内存，超出了这个设置值，就会抛出OutOfMemory异常。. ago. -Xms and -Xmx does not determine the amount of memory your application needs. , -XX:MaxRAMFraction, -XX:MaxRAMPercentage, -Xmx), always make sure you allocate at least 25% more memory to your container (i. e. Also if you are using Java 8, no other additionnal args are necessary other than Xmx and Xms. This is useful if your program will consume a large amount of heap memory right from the start. This page will help you understand basic concepts behind hosting a minecraft server. 默认 (MinHeapFreeRatio参数可以调整)空余堆内存小于40%时，JVM就会增大堆直到-Xmx的最大限制. Xmx sets the maximum amount of used RAM, Xms sets the amount of RAM allocated on start. It's possible that under Java 8 your application simply needs somewhat more memory. It is just a warning message about another JVM parameter -XX:PermSize which is not supported since Java 8, because Permanent Generation was replaced with Metaspace. 0. 10 Operating System: Windows 8. To tell the JVM the initial size of the heap, use the -Xms option as well; e. -XX:MaxPermSize=size Sets the maximum permanent generation space size. 4 Answers. I suggest leaving it out and replacing it with -Xincgc instead. Your Xms and Xmx should probably. Xmx Xms Xmn-XX:SurvivorRatio . jar My initial java version. Keep -Xms Small. As such, these numbers being the same is not necessary and sometimes not a good idea. XXMaxPermSize 1024M -showsplash org. 将 -Xms 和 -Xmx 设置为相同的值可以带来以下好处：. -Xmxsize Specifies the maximum heap size. Consider when Xms == Xmx, I'd expect the heap usage would never quite meet Xms. Failed to start the minecraft server joptsimple. como instalar mods en minecraft para celular4. Updated on October 18, 2021 by Arpit Mandliya. Nota: Lo simplificamos como memoria máxima y mínima aunque es un poco más complejo que esto, tiene que ver con el heap de Java. java version "1. The -Xmx parameter belongs to the (nonstandard) JVM options, and--being an option--needs. -Xms is the start value of your Java heap size. 3 Java Version: 1. They denote the New generation size. To further tune your memory usage in a. It is commonly known that it is possible to limit the Java heap size with -Xmx<amount><unit>, where unit is the data amount unit like Gigabyte, Megabyte, etc. Share. El primer grupo de parámetros de configuración: -xms, -xmx, -xx: newsize, -xx: maxNewsize, -xmn. . What are your memory settings in MineOS? Just curious what your Java xms and xmx settings are in the WebGUI for MineOS? Should they be the same number? My heap was at 116% last night with settings for both at 1024 so I bumped both up to 2056 (after everyone was done for the night) lol. Enjoy ad-free music across all genres and decades, news and issues, talk shows and podcasts, comedy, and more. and so on. Typically, there is a script of some form that has a java invocation in it. Aloque mais memória. 4. Specifying. The -Xms and -Xmx options are used to set the initial and maximum heap sizes, respectively, for the Java Virtual Machine (JVM). There are three types of options that you can add to your JVM, standard, non-standard and advanced options. 例如，启动JVM（如下所示）将使用256 MB内存启动，并且允许进程使用最多2048 MB内存：. -Xms 堆内存的初始大小，默认为物理内存的1/64 -Xmx 堆内存的最大大小，默认为物理内存的1/4 -Xmn 堆内新生代的大小。. So when you set -Xmx and -Xms, you will get a portion of virtual memory allocated as needed. 紧接. Some java -Xms -Xmx examples : # Start with 128MB of memory, and allow the Java process to use up to 1024MB of memory. -Xms 16m. in my experience the game runs the best without setting -Xms, and if I set it the same as -Xmx then performance is terrible. XMX is the maximum amount of memory that can be allocated. and so on. Select "Minecraft. It varies on implementation and version, but usually it depends on the VM used (e. Yes. See Using -X command-line options for more information about the <size> parameter. -XX:MaxGCPauseMillis=200 -XX:ParallelGCThreads=<var> . In order to allocate more RAM, the launcher needs to be accessed. Therefore, the -Xmx flag in Java, changes the maximum heap size for the JVM. Hello guys i want to ask about how can i increase the memory usage of the game server. # Decrease Java heap size (-Xmx/-Xms) # Decrease number of Java threads # Decrease Java thread stack sizes (-Xss) # Set larger code cache with -XX:ReservedCodeCacheSize=. To configure the heap size, add the Xms and Xmx JVM arguments to a custom JVM options file with the extension . eclipse. Activa la optimización del heap de Java. Increasing the JVM heap memory using Xmx doesn't work. However -Xmx does not limit the total amount of memory that the JVM. Simplified: "-Xmx4G -Xms4G" = 4GB of memory allocated to Minecraft. Advanced JVM args42. The -Xmx option and -Xms option in combination are used to limit the Java heap size. Por ejemplo, a partir de una JVM como la siguiente arrancará con 256 mb de memoria, y permitirá que el proceso use hasta 2048MB de memoria: java -Xmx2048m -Xms256m. 28 February 2012. but when i am running this command i am getting these errors. e. 5 条答案. Minimum java heap size. options. bat file I use for my private modded server for me and a bunch of friends, and it works. This is also why reducing -Xmx to 3000M as you did makes your programm work fine. -Xms<size>. Solution. 2) The default maximum heap space is 1/2 of the physical memory of size up to 192 bytes and 1/4th of physical memory for a size up to 1G. By default, the size is in bytes. . You can replace that flag with either -Xmx4G or -Xmx4096M to raise this limit to 4GB. -Xms 3670k-Xmx 64m. 10 is known to have some performance issues compared to other versions, and this is made even worse by the fact that TerraFirmaCraft utilizes the full 256 world height. org. If you're on windows, Hold down the windows key and press "pause Break" key (near your scroll lock). (Oh, you specified, yeah you need to pass it into the "Java" command you are. Also Java configuration options (command line parameters) can be. You can adjust the memory settings in the Minecraft Launcher. JVM Options Overview. Where it says "JVM Arguments" (at the bottom) type in: "-Xmx [amount of memory in GB]G -Xms [same amount of memory in GB]G". More specifically, the java launcher needs to be used as follows: java [options] -jar file. . -Xmn is an allocated space that the Java GC passes often. -Xms 初始Heap大小-Xmx java heap最大值-Xmn young generation的heap大小 JVM有2个GC线程.