Error occurred during initialization of vm initial heap size

In this short tutorial, I will be sharing how to solve the error «initial heap size set to a larger value than the maximum heap size». I have divided the post into two parts. In the first part, we will produce the error by passing VM/JVM parameters through the command line. In the second part, we will fix the error.

Read Also: Could not reserve enough space for object heap

What is -Xms and -Xmx

-Xms: In java, Xms is the minimum heap size that is allocated at initialization of JVM.
-Xmx: Xmx represents the maximum heap size JVM can use.

1. Producing the Error

Suppose we have below HelloWorld java program:

  public class HelloWorld { 

       public static void main( String args[] ) {
            System.out.println("Simple Java Program");       
       }
  }

Compile the above HelloWorld java program in command line/terminal:

javac HelloWorld.java

1. Run the above program by passing a single JVM parameter:

Passing -Xms

java -Xms512m HelloWorld

The above command will print the following output:

Simple Java Program

2. Run the HelloWorld program by passing multiple JVM parameters:

Passing -Xms and -Xmx  

java -Xms512m -Xmx1024m HelloWorld

After running the above command, you will get the following output:

Simple Java Program

If the value of Xms(minimum heap size) is greater than the value of Xmx(maximum heap size) than it will produce this error as shown below:

java -Xms2g -Xmx1g HelloWorld

Error occurred during initialization of VM
Initial heap size set to a larger value than the maximum heap size

Currently, the value of Xms(minimum heap size) is 2 gigabytes and Xmx(maximum heap size) is 1 gigabyte. 

2. [Fixed] Initial heap size set to a larger value than the maximum heap size

To get rid of this error, the value of Xmx(maximum heap size) should always be greater than or equal to Xms(minimum heap size).

Run the HelloWorld program with the value of Xms(minimum heap size) set to 1 gigabyte and Xmx(maximum heap size) set to 2 gigabytes.

java -Xms1g -Xmx2g HelloWorld

Simple Java Program

That’s all for today, please mention in comments in case you have any questions related to the initial heap size set to a larger value than the maximum heap size error.

I was getting «Invalid initial heap size: -Xms=1024M» while starting JVM and even after changing the maximum heap size from 1024 to 512M it keeps crashing by telling «Invalid initial heap size: -Xms=512m, Could not create the Java virtual machine». I check almost everything starting from checking how much physical memory my machine has to any typo in JVM parameters, only to find out that instead of M, I had put MB there. Java accepts both the small case and the capital case for Kilo, Mega, and Gigs. you can use m or M, g or G, etc but never used MB, GB, or KB.  A similar problem can occur with the maximum heap size specified by -Xmx. Also from Java 6 update 18, there is a change in default heap size in JVM.  

Invalid initial and maximum heap size in JVM

Here is a list of common errors while specifying maximum and minimum heap size in Java :

java -Xmx4056M -Xms4056M HelloWorld

Issue:  Error occurred during initialization of VM , The size of the object heap + VM data exceeds the maximum representable size

java -Xmx1056M -Xms2056M HelloWorld

Issue:  Error occurred during initialization of VM , Incompatible minimum, and maximum heap sizes specified

Cause: the value of -Xms is higher than -Xmx

java -Xms2056M HelloWorld

Issue: Error occurred during initialization of VM , Could not reserve enough space for object heap

Cause: Only -Xms was provided and -Xmx was not provided. you will also get this error if you have a typo and instead of -Xmx you have specified -Xms two times, happened to my friend last time.

Command: java -Xms1024 M -Xmx1024M HelloWorld

Issue: Error occurred during initialization of VM , Too small initial heap

Cause: If you had space between 1024 and M then JVM assumes the size of -Xms as 1024 bytes only and prints an error that it’s too small for JVM to start.

public class HelloWorld{
  public static void main(String args[]){
      System.out.println("HelloWorld to Java");
  }
}

$ test@nykdev32:~ java -version
java version "1.6.0_14"
Java(TM) SE Runtime Environment (build 1.6.0_14-b08)
Java HotSpot(TM) Server VM (build 14.0-b16, mixed mode)

$ test@nykdev32:~ java -Xmx4096M HelloWorld
Invalid maximum heap size: -Xmx4096M
The specified size exceeds the maximum representable size.
Could not create the Java virtual machine.

$ test@nykdev32:~ java -d64 -Xmx4096M HelloWorld
HelloWorld to Java

If you run the Java program from the command line then you will also get a message that say Could not create the Java virtual machine with each invalid heap error but if you run your program from Eclipse you will not get the message «Could not create the Java virtual machine», instead, you will just see an error message in the console.

Regarding default heap size in Java, from Java 6 update 18 there are significant changes in how JVM calculates default heap size in 32 and 64-bit machines and on client and server JVM mode:

1) Initial heap space and maximum heap space is larger for improved performance.

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. So for a 1G machine maximum heap size is 256MB 2.maximum heap size will not be used until the program creates enough objects to fill the initial heap space which will be much lesser but at least 8 MB or 1/64th part of Physical memory up to 1G.

3) For Server Java virtual machine default maximum heap space is 1G for 4GB of physical memory on a 32 bit JVM. for 64 bit JVM it’s 32G for physical memory of 128GB.

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