What is the maximum file size that the JVM can handle?

I wanted to know the maximum size Which can be read by Java code?

I wanted to handle a file size of 100mb . is it possible?

If possible, what are the initial JVM settings that I have to complete?

Please recommend some recommendations for working with the file. e.g. use ObjectInputStream, FilterInputStream etc. use a byte array to store the contents of the file, etc.

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What is the largest number you can write? . The maximum size.

The total file size does not matter if you read it in chunks; there is no rule in the world that states that you should read in your 100 megabyte file at a time, you can read it in, say, 10 megabytes. What really matters is how you use this input data and whether you need to store the raw data product completely (for example, if the data is a three-dimensional model of the building, how you need to represent it) or only (for example, finding the first ten matches with some sentence from a huge text file).

Since there are many possible ways to process data, there is no hidden answer to your question.

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The only maximum that I know of is the maximum message length () is long. This length is 2 ^ 62 - 1 or very large.

Java will not store the entire file in memory at one time. If you want to keep part of the file in memory, you must use one of the Buffered classes (the class name begins with Buffered). These classes buffer part of the file for you based on the size of the buffer you set.

The exact classes you should use depend on the data in the file. If you are more specific, we can help you figure out which classes to use.

(One modest note: Seriously, 100 MB? That's pretty small.)

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There is no maximum file size that can be read theoretically, but I think it is Integer.MAX_VALUE because you cannot initialize a charBuffer size larger than Integer.MAX_VALUE

 char[] buffer = new char[/* int size */]; char[] buffer = new char[Integer.MAX_VALUE]; // maximum char buffer BufferedReader b = new BufferedReader(new FileReader( new File("filename"))); b.read(buffer); 
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There is no specific maximum file size supported by Java, it all depends on which OS you are running. 100 megabytes will not be a problem, even on a 32-bit OS.

You did not say whether you want to immediately read the entire file in memory. You may find that you need to process only part of the file at a time. For example, a text file can process a string at a time, so there is no need to download the entire file. Just read the line at a time and process each.

If you want to read the entire file into one block of memory, you may need to change the default heap size for your JVM. Many JVMs have a default value of 128 MB, which is probably not enough to download your entire file and still have enough space for other useful things. Check the documentation for your JVM to find out how to increase heap size distribution.

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As long as you have more than 100 MB of free space, you should immediately load the entire file into memory, although you probably will not need it.

BTW: In terms of what the letter means

 M = Mega or 1 million for disk or 1024^2 for memory. B = Bytes (8-bits) b = bit eg 100 Mb/s m = milli eg mS - milli-seconds. 

100 milliseconds makes sense only for compressed data, but I assumed that this is not what you are talking about.

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Source: https://habr.com/ru/post/1333448/


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