Invalid Maximum Heap Size | Why It Happens And How To Get Rid Of It

The ‘Invalid Maximum Heap Size’ error can result from several reasons but the good thing is that it’s fairly easy to resolve.

Minecraft is a virtual 3D game with block animation. The most impressive part of the game is that it allows people to play the game on their own as well as with friends and other online players through steadfast servers.

  • Some of these servers belong to the game’s official servers while others are created by the players.

These servers provide a whole new experience as they allow you to build your world inside Minecraft or join the realms created by other players.

Any player can design, create or join a server in Minecraft. The creator of a server has the advantage of changing the world’s rules and environment however they want, while also having access to the command prompts.

It is considerably easy to create a server in Minecraft if you have enough knowledge. However, sometimes errors can make it seem infuriating and can make it impossible to set up your server. This is why these issues should be fixed immediately.

Invalid Maximum Heap size 

Is one such problem the players have to face when creating their servers. The most likely cause of this error is that a player tries to allocate more RAM to their Minecraft server.

The error makes it difficult to run your server correctly because it will stop providing more memory to your server. 

Getting Rid Of The Invalid Maximum Heap Size Issue In Minecraft

Here are some ways to get rid of this error.

Allocate less Memory

Allocating more memory to your Minecraft server than it holds is a common cause of this error.

If you don’t have sufficient memory to allot to your server then it is advised that you get better RAM. It will help solve the error Invalid Maximum Heap Size.

Switch to 64-bit Java

When you switch from 32-bit Java to 64-bit Java, the error is likely to be resolved. Here is a simple guide on how to install 64-bit Java:

  • Firstly, from Java’s official website download 64-bit Java.

  • When you’re done with downloading, select the 64-bit Windows offline download option.

  • Select the location of your choice for the folder. It is suggested that you choose a desktop so that you can access the file easily.

  • Click on the Save button when you’re done.

  • Close all of the running applications currently on your computer. It is advised that you exit all processes using the task manager.

  • After completing all of the above-mentioned steps, start the installation process by double-clicking on the saved file’s icon.

You should also change your newly installed 64-bit Java command to:

java -Xmx4096M -Xms4096M -jar craftbukkit.jar

Invalid Maximum Heap Size Issue& Its FAQ’s

Here are some frequently asked questions regarding error Invalid Maximum Heap Size whether it’s for your own Java application or any Java web or application server such as Tomcat, JBoss, or WebLogic, This FQA section applies to all of them.

2GB or 4GB? Find what is maximum heap size for 32 bit JVM?  

This particular confusion arises because of a sign bit, a lot of programmers think in terms of signed integer and they confuse maximum addressable memory (size of address bus) for 32-bit architecture is 2^32-1 or 2GB and this confusion is backed up by the fact that you cannot supply maximum heap space like 2GB on a windows device.

The programmers fail to realize that memory has nothing to do with a signed or unsigned bit because there is no negative memory address. So in summary, the ideal limit for maximum heap size on 32 bit JVM is 4GB and for 64 bit JVM, it’s 2^64.

Why you cannot allocate a full 4GB and can only allocate less than that?

The most important point to keep in mind regarding why you cannot allocate 4GB and only allocate considerably less than 4GB to a java process on a 32-bit machine is that the threads created in the java process have their stack space and that also has to fit into this 4GB limit.

Usually, because of OS overhead, this limit is 3.2GB and not 4GB. Now this default thread-stack space (Xss) varies and is different on different operating systems and therefore there is a difference between the total memory you can allocate to the heap and the memory mentioned.

  • So, in short, we can get a pretty good idea of practical available space by,

Max Heap = 3.2GB – total thread-stackspace.

One fast and easy alternative to using more heap on a multi-threaded java app is to try reducing your Xss.

If Maximum Heap Space Around 1600M Why can’t JVM Start on Windows XP?

This problem is most commonly faced on Windows platforms like Windows XP, which tries to assign a continuous load of memory as requested by -Xmx JVM parameters.

Windows reserves some space for normal functioning but also assigns memory around half of the memory address bar, which in turn lessens contiguous memory space around less than 2GB, around 1500 to 1600M and when you try to give more memory than this size, JVM displays an error as.

  • Could not create the Java virtual machine.

Invalid initial heap size: -Xms1.5G

If The Maximum Heap Space Around 1600M on Windows XP and JVM Show An Error, Should I Replace Windows?

This set limit on heap space is because of Windows operating system’s behavior. On other platforms such as Linux or Solaris, you can determine maximum heap space, greater than this size.

it is important to remember that the maximum heap size for 32 bit or 64 bit JVM will invariably be less than the hypothetical limit of addressable memory. 

Why Does Linux or Solaris Enable a More Extended Maximum Heap Size Than Windows for The Same, 32 bit JVM?

There are multiple reasons why this happens but the most agreeable reason is that Windows try’s to assign or allocate a contiguous load of memory as Java heap space whereas this is not the exact case with Linux or Solaris

Can We Set More Than 4GB as The Maximum Heap Size For 32 bit JVM running On a 64 bit or x64 Operating System?

In theory, you can set up to 4GB for 32 bit JVM but cannot exceed that limit. x64 Servers have bigger memory for and since every process can have almost 2^64 bit it may seem alright for 32 bit JVM to accept 4GB as the maximum heap size.

In practice, however, due to many complications, it doesn’t always work

8GB or 16GB? What is The Maximum Heap Size For 64 bit or x64 JVM? 

The dilemma of available physical memory on the machine raises this question. At the current stage, no system has 2^64 bit of physical memory or RAM, only high-end servers have a memory of approximately 8G, 16GB, or 32GB.

Theoretical maximum memory however for x64 machines is 2^64 bit but again it depends on how much memory your operating systems permits. 

If Physical Memory is Less Than 1GB, Can More Than 1GB Be Designated Ss Heap Space?

In theory, it is possible, because the operating systems can utilize virtual memory and swap pages between physical memory and virtual memory when there is no space in physical memory.

Practically, however, if you are running on windows then it depends on how far you can go, there are many reasons why errors may occur in this scenario.

My Name is Hazel, I am Content Manager @freeholidaywifi. In my spare time i like to write about Tech, Software's & more. Other then that i love football & travelling new places.

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