You have taken the quote out of context. The full context is this:
64-bit Java
How is native code affected?
...
When porting 32-bit native code to 64-bit Java platforms, you will need to modify you code to be 64-bit clean. This involves examining your C/C+ + code and looking for code that assumes the size of a pointer to be 4 bytes or that a pointer can be cast and stored in an integer. Long data types are also troublesome when porting 32-bit code. You should avoid the use of longs if at all possible since longs have different sizes on different operating systems even in 64-bit. Windows 64-bit platforms define longs to be 4 bytes but most Unix operating systems specify that longs are 8 bytes in size. For more details, refer to the links below under learning more about 64-bit programming.
To answer your questions:
Java size of long type?
The Java long type is 64 bits on all platforms.
What does this quote mean?
It is self evident, but it is clearly NOT referring the the Java long type. It is referring to the use of the C or C++ long type in native code.
When I want to store value more than ~2^31, how JVM store this value?
In Java code, use long. It works. The JVM implementation takes care of it in different ways on different platforms. Don't worry about it.
In C / C++ native code you have a problem if you want your code to be portable. But the original article provides you with links to help you get your head around the problem.
In calculations, JVM use RAX, or EAX register?
The Java language specification requires that long has a 64 bit (no less, no more) representation, and that all long op long arithmetic is performed with at least 64 bits of precision so that the answer is the same on all platforms.
The actual implementation depends on the platform. The JVM / JIT compiler will (most likely) chose registers and instructions that are most efficient for the current platform.
Bear in mind that the JVM you run on a 32 bit Windows Intel platform is different to one for a 64 bit Windows Intel platform, or Solaris, ARM, and so on. For many of those platforms there are no registers called RAX and EAX.
But if you really need to know, look at the source code, or use the JVM option for dumping the native code emitted by the JIT compiler.
Answer from Stephen C on Stack OverflowGeeksforGeeks
geeksforgeeks.org › java › difference-between-byte-short-int-and-long-datatype-in-java
Difference Between byte, short, int and long Datatype in Java - GeeksforGeeks
July 23, 2025 - Among these, the integer data types are byte, short, long, and int. The integer data types are used to store numeric values. In this article, we will discuss the difference between these four Integer data-types. JAVA does not support an unsigned version of these integer data types. The main basis of difference is size and range.
DataCamp
datacamp.com › doc › java › java-data-types
Java Data Types
There are eight primitive data ... int: Size: 32-bit · Range: -231 to 231-1 · Usage: Default choice for integer values. int i = 100000; long: Size: 64-bit ·...
jvm - Java size of long type - Stack Overflow
On Oracle.com I have read: You should avoid the use of longs if at all possible since longs have different sizes on different operating systems even in 64-bit. Windows 64-bit platforms define l... More on stackoverflow.com
Which is larger? Long vs Double
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January 19, 2023[Java] Size of a long?
Instead of thinking about bytes, think about bits (noting that 8 bits = 1 byte). So a long is 64 bits, and so in base 2, you would need 64 zeroes and ones to represent a long. Since 4 bits can be represented in a hexadecimal digit, you would need 16 hexadecimal digits to represent 64 bits. More on reddit.com
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November 25, 2016Java Beginner: Confused on why "L" is needed at the end of a long value
Surely the compiler should know using the datatype declaration at the beginning of the statement alone? The data type declaration and the number literal are interpreted separately, so the compiler can't infer the data type when considering the number literal. Even if it could do this, there are many cases where there isn't a declared data type that the compiler could rely on. (such as when used as a method argument, or when a number literal is used in a larger expression). So the language needs some unambiguous way for the programmer to say that "this number is a long", or "this number is a float", or "this number is a double". More on reddit.com
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June 30, 2020Videos
11:27
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Size of different Data Types in Java - YouTube
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The byte, short, and long Data Types in Java - YouTube
Java Tutorial: long datatype in Java| Complete Java course for ...
Oracle
docs.oracle.com › javase › tutorial › java › nutsandbolts › datatypes.html
Primitive Data Types (The Java™ Tutorials > Learning the Java Language > Language Basics)
The signed long has a minimum value of -263 and a maximum value of 263-1. In Java SE 8 and later, you can use the long data type to represent an unsigned 64-bit long, which has a minimum value of 0 and a maximum value of 264-1. Use this data type when you need a range of values wider than those ...
JA-VA Code
java-performance.info › home › java: byte, short, int, long, char, boxing/unboxing
Long to Integer Java: A Practical Guide
September 25, 2023 - The byte data type is the smallest integer type in Java, occupying just 8 bits (1 byte). Despite its size, it packs quite a punch when it comes to memory efficiency. It can hold values ranging from -128 to 127.
IBM
ibm.com › docs › en › i › 7.4.0
COBOL and Java Data Types
We cannot provide a description for this page right now
Quora
quora.com › What-is-the-difference-between-byte-short-int-and-long-in-Java
What is the difference between byte, short, int, and long in Java? - Quora
Answer (1 of 3): These are consider as a data type in java Byte can hold 8 bit Short can hold 16 bit Int can hold 32 bit Long can hold 64 bit
W3Schools
w3schools.com › java › java_data_types.asp
Java Data Types
assert abstract boolean break byte case catch char class continue default do double else enum exports extends final finally float for if implements import instanceof int interface long module native new package private protected public return requires short static super switch synchronized this throw throws transient try var void volatile while Java String Methods
Datacadamia
datacadamia.com › lang › java › long
Java - long - Long (integer 64 bit)
August 30, 2024 - In Java, the long data type stores integer on 64 bit while the integer data type stores integer on 32bit. The primitive wrapper java/lang/LongLong is a subclass of java/lang/NumberNumber in java Long is an integer that is encoded with 64 bit but you have also int on 32 bit.
Reddit
reddit.com › r/javahelp › which is larger? long vs double
r/javahelp on Reddit: Which is larger? Long vs Double
January 19, 2023 -
I’ve tried looking for definitive answers but the only difference I see seems to be based on the precision of the numbers?
Which data type is larger and which one is smaller?
Top answer 1 of 8
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double is made of 1 bit sign 52 bit mantissa and 11 bit exponent and long is made of 1 bit sign and 63 bit number. So double can have larger values, and they both take 64 bits in your memory. So double has the precision of at most 16 digits and long of at most 19 digits. (Also, a double can have a value of Infinity) If you're looking for an object that can store very large numbers, use BigInteger or BigDecimal, their value is only limited by how much memory your computer has and they can do precise math.
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If you're asking about the amount of space that will be occupied by a long or a double, then the answer is that they're both the same: 64 bits. If you're asking about the range of values that can be represented with a long or a double, then the answer is that double has a larger range of values, but it suffers from floating-point precision issues; meaning that it can't represent most values in its range (which gets especially noticeable with larger values).
Python documentation
docs.python.org › 3 › library › stdtypes.html
Built-in Types — Python 3.14.3 documentation
1 week ago - The advantage of the range type over a regular list or tuple is that a range object will always take the same (small) amount of memory, no matter the size of the range it represents (as it only stores the start, stop and step values, calculating individual items and subranges as needed).
Oracle
docs.oracle.com › javase › 8 › docs › api › java › lang › Long.html
Long (Java Platform SE 8 )
October 20, 2025 - Parses the string argument as an unsigned decimal long. The characters in the string must all be decimal digits, except that the first character may be an an ASCII plus sign '+' ('\u002B'). The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseUnsignedLong(java.lang.String, int) method.
GeeksforGeeks
geeksforgeeks.org › java › java-data-types
Java Data Types - GeeksforGeeks
Size : 4 bytes ( 32 bits ) Java ... used when int is not sufficient for large values. Syntax: long longVar; Size : 8 bytes (64 bits) Java ·...
Published January 16, 2026
Reddit
reddit.com › r/learnprogramming › [java] size of a long?
r/learnprogramming on Reddit: [Java] Size of a long?
November 25, 2016 -
For a school project, we're supposed to work with longs in encoding and reading from .dat and .idx files.
So for example, encoding a 0 into a file would encode 0000 0000 0000 0000. I'm trying to puzzle through the definition of longs, and according to the java docs, a long is 64 bits, or 8 bytes.
So for a long 0000 0000 0000 0000, how does this correspond to 8 bytes if there are 16 zeroes in total?
Top answer 1 of 3
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Instead of thinking about bytes, think about bits (noting that 8 bits = 1 byte). So a long is 64 bits, and so in base 2, you would need 64 zeroes and ones to represent a long. Since 4 bits can be represented in a hexadecimal digit, you would need 16 hexadecimal digits to represent 64 bits.
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Ps: When i writeLong(0) to the file, it shows 0000 0000 0000 0000 When I writeLong(-1) to the file, it shows FFFF FFFF FFFF FFFF. So yeah, i'm a bit confused why it's only writing 16 bits (are they bits?) instead of 64
Examveda
examveda.com › home › java program › data types and variables › question
What is the size of a long variable in Java
September 14, 2023 - So, the size of a long variable in Java is 8 bytes.
Substack
alexanderobregon.substack.com › p › median-of-a-data-stream-with-two
Median of a Data Stream with Two Heaps in Java
3 days ago - Size checks decide which case applies, then peek() pulls the boundary values without changing heap contents. The even-count case casts to long before the add, which avoids overflow when two large int values are summed, and the / 2.0 keeps the return type as double so midpoints like 2.5 stay accurate.
Codementor
codementor.io › community › primitive data types in java: understand the core essentials
Primitive Data Types In Java: Understand The Core Essentials | Codementor
March 22, 2024 - long myLong = 2147483648L; long myOtherLong = 2147483649l; For handling decimal numbers, Java offers two primitive data types: float and double.
Processing
processing.org › reference › long.html
long / Reference / Processing.org
While integers can be as large as 2,147,483,647 and as low as -2,147,483,648 (stored as 32 bits), a long integer has a minimum value of -9,223,372,036,854,775,808 and a maximum value of 9,223,372,036,854,775,807 (stored as 64 bits).
W3Schools
w3schools.com › c › c_data_types_extended.php
C More Data Types (Extended Types)
*Note: The size of these types can differ between systems (for example, 2 or 4 bytes, or 4 or 8 bytes), depending on whether the computer is older or newer, 32-bit or 64-bit, and which compiler is used.
Quora
quora.com › Q1-What-is-the-size-of-the-int-data-type-in-Java
Q1.What is the size of the int data type in Java? - Quora
Answer (1 of 7): The size of the int data type in java is 4. In java,it is a type of Integral data type. int data type has wide range of uses. The range of int data type in java is -2,147,483,648 to 2,147,483,648. The int data type in java is, ...